Remove gem and docker files. (#137200)

Gem files were used to install cocoapods which now is being provisioned as part of the ruby cipd package.

This is also deleting the docker file used for Cirrus testing.

Bug: https://github.com/flutter/flutter/issues/136377

dev/ci/README.md

-This directory includes scripts and tools for setting up Flutter's continuous
-integration environments.
-
-## Cirrus Linux
-
-Flutter's Linux tasks run on a custom Docker image. The `Dockerfile` for this
-image can be found at [/dev/ci/docker_linux/Dockerfile](https://github.com/flutter/flutter/blob/master/dev/ci/docker_linux/Dockerfile).
-On each new change to this `Dockerfile`, Cirrus will build a new version of
-the Docker image as a dependency to any Linux tests. It is no longer necessary
-to manually build and push the Docker image locally.
-
-There are some factors external to the actual `Dockerfile` that would
-necessitate rebuilding the Docker image, such as upstream code changes, (Linux
-distribution) repository updates or a file that gets `COPY`ied into the image
-changing. In this case, a trivial `Dockerfile` change (such as a comment)
-would invalidate the cache and trigger a rebuild.

dev/ci/docker_linux/Dockerfile

-# Flutter (https://flutter.dev) Development Environment for Linux
-# ===============================================================
-#
-# This environment passes all Linux Flutter Doctor checks and is sufficient
-# for building Android applications and running Flutter tests.
-#
-# To build iOS applications, a Mac development environment is necessary.
-#
-# This includes applications and sdks that are needed only by the CI system
-# for performing pushes to production, and so this image is quite a bit larger
-# than strictly needed for just building Flutter apps.
-
-# Last manual update 2021-09-24 (changing this comment will re-build image)
-
-FROM ubuntu:focal@sha256:33a5cc25d22c45900796a1aca487ad7a7cb09f09ea00b779e3b2026b4fc2faba
-MAINTAINER Flutter Developers <flutter-dev@googlegroups.com>
-
-ENV TZ=America/Los_Angeles
-RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
-
-RUN apt-get update -y && \
-  apt-get upgrade -y
-
-# Install basics
-RUN apt-get install -y --no-install-recommends \
-  git \
-  wget \
-  curl \
-  zip \
-  unzip \
-  apt-transport-https \
-  ca-certificates \
-  gnupg
-
-# Add repo for chrome stable
-RUN wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | apt-key add -
-RUN echo 'deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main' | \
-    tee /etc/apt/sources.list.d/google-chrome.list
-
-# Add repo for gcloud sdk and install it
-RUN echo "deb [signed-by=/usr/share/keyrings/cloud.google.gpg] https://packages.cloud.google.com/apt cloud-sdk main" | \
-    tee -a /etc/apt/sources.list.d/google-cloud-sdk.list
-
-RUN curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | \
-    apt-key --keyring /usr/share/keyrings/cloud.google.gpg add -
-
-RUN apt-get update && apt-get install -y google-cloud-sdk && \
-    gcloud config set core/disable_usage_reporting true && \
-    gcloud config set component_manager/disable_update_check true
-
-# Install the dependencies needed for the rest of the build.
-RUN apt-get update && apt-get install -y --no-install-recommends \
-  openjdk-17-jdk \
-  build-essential \
-  default-jdk-headless \
-  gcc \
-  google-chrome-stable \
-  lib32stdc++6 \
-  libglu1-mesa \
-  libstdc++6 \
-  locales \
-  nodejs \
-  npm \
-  ruby \
-  ruby-dev && \
-  apt-get clean
-
-ENV JAVA_HOME="/usr/lib/jvm/java-17-openjdk-amd64"
-
-# Install the Android SDK Dependency.
-# In the event of an update you can visit this page: https://developer.android.com/studio and scroll to the bottom to find
-# the latest version to update. Be wary of any changes to the name of the package as you will need to adjust the paths below.
-ENV ANDROID_SDK_URL="https://dl.google.com/android/repository/commandlinetools-linux-9477386_latest.zip"
-ENV ANDROID_TOOLS_ROOT="/opt/android_sdk"
-RUN mkdir -p "${ANDROID_TOOLS_ROOT}"
-RUN mkdir -p ~/.android
-# Silence warning.
-RUN touch ~/.android/repositories.cfg
-ENV ANDROID_SDK_ARCHIVE="${ANDROID_TOOLS_ROOT}/archive"
-RUN wget --progress=dot:giga "${ANDROID_SDK_URL}" -O "${ANDROID_SDK_ARCHIVE}"
-RUN unzip -q -d "${ANDROID_TOOLS_ROOT}" "${ANDROID_SDK_ARCHIVE}"
-
-RUN mkdir "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools"
-
-RUN mv "${ANDROID_TOOLS_ROOT}/cmdline-tools/NOTICE.txt" "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools"
-RUN mv "${ANDROID_TOOLS_ROOT}/cmdline-tools/bin" "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools"
-RUN mv "${ANDROID_TOOLS_ROOT}/cmdline-tools/lib" "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools"
-RUN mv "${ANDROID_TOOLS_ROOT}/cmdline-tools/source.properties" "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools"
-
-# Suppressing output of sdkmanager to keep log size down
-# (it prints install progress WAY too often).
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "tools" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "build-tools;28.0.3" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "platforms;android-30" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "platform-tools" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "cmdline-tools;latest" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "extras;android;m2repository" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "extras;google;m2repository" > /dev/null
-RUN yes "y" | "${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin/sdkmanager" "patcher;v4" > /dev/null
-RUN rm "${ANDROID_SDK_ARCHIVE}"
-ENV PATH="${ANDROID_TOOLS_ROOT}/cmdline-tools/tools:${PATH}"
-ENV PATH="${ANDROID_TOOLS_ROOT}/cmdline-tools/tools/bin:${PATH}"
-# Silence warnings when accepting android licenses.
-RUN mkdir -p ~/.android
-RUN touch ~/.android/repositories.cfg
-
-# Add npm to path.
-ENV PATH="/usr/bin:${PATH}"
-
-# Set locale to en_US
-RUN locale-gen en_US "en_US.UTF-8" && DEBIAN_FRONTEND=noninteractive dpkg-reconfigure locales
-ENV LANG en_US.UTF-8
-
-# Install dependencies for desktop flutter run
-RUN apt-get install -y --no-install-recommends \
-  clang \
-  cmake \
-  libgtk-3-dev \
-  ninja-build \
-	pkg-config \
-	x11-xserver-utils \
-	xauth \
-	xvfb && \
-  apt-get upgrade -y --no-install-recommends && \
-  apt-get clean

dev/ci/docker_linux/Gemfile

-# When editing this file, update the comment starting "# Gemfile last edited"
-# in dev/ci/docker_linux/Dockerfile to retrigger a Docker build on Cirrus.
-
-source "https://rubygems.org"

dev/ci/docker_linux/Gemfile.lock

-GEM
-  remote: https://rubygems.org/
-  specs:
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-
-BUNDLED WITH
-  2.0.2

dev/ci/docker_linux/README.md

-This directory includes scripts to build the docker container image used for
-building flutter/flutter in our CI system (currently [Cirrus](cirrus-ci.org)).
-
-To run the scripts, you have to set up `docker` and `gcloud`. Please
-refer to the [internal flutter team doc](go/flutter-team) for how to set up in a
-Google internal environment.

dev/ci/mac/Gemfile

-# This Gemfile is for the setup step of the Cirrus Mac tasks
-source 'https://rubygems.org'
-
-# Don't pin cocoapods so we can catch breakages from upstream changes, e.g.
-# https://github.com/flutter/flutter/issues/41144
-gem 'cocoapods'

dev/ci/mac/Gemfile.lock

-GEM
-  remote: https://rubygems.org/
-  specs:
-    CFPropertyList (3.0.5)
-      rexml
-    activesupport (6.1.7.6)
-      concurrent-ruby (~> 1.0, >= 1.0.2)
-      i18n (>= 1.6, < 2)
-      minitest (>= 5.1)
-      tzinfo (~> 2.0)
-      zeitwerk (~> 2.3)
-    addressable (2.8.0)
-      public_suffix (>= 2.0.2, < 5.0)
-    algoliasearch (1.27.5)
-      httpclient (~> 2.8, >= 2.8.3)
-      json (>= 1.5.1)
-    atomos (0.1.3)
-    claide (1.1.0)
-    cocoapods (1.11.3)
-      addressable (~> 2.8)
-      claide (>= 1.0.2, < 2.0)
-      cocoapods-core (= 1.11.3)
-      cocoapods-deintegrate (>= 1.0.3, < 2.0)
-      cocoapods-downloader (>= 1.4.0, < 2.0)
-      cocoapods-plugins (>= 1.0.0, < 2.0)
-      cocoapods-search (>= 1.0.0, < 2.0)
-      cocoapods-trunk (>= 1.4.0, < 2.0)
-      cocoapods-try (>= 1.1.0, < 2.0)
-      colored2 (~> 3.1)
-      escape (~> 0.0.4)
-      fourflusher (>= 2.3.0, < 3.0)
-      gh_inspector (~> 1.0)
-      molinillo (~> 0.8.0)
-      nap (~> 1.0)
-      ruby-macho (>= 1.0, < 3.0)
-      xcodeproj (>= 1.21.0, < 2.0)
-    cocoapods-core (1.11.3)
-      activesupport (>= 5.0, < 7)
-      addressable (~> 2.8)
-      algoliasearch (~> 1.0)
-      concurrent-ruby (~> 1.1)
-      fuzzy_match (~> 2.0.4)
-      nap (~> 1.0)
-      netrc (~> 0.11)
-      public_suffix (~> 4.0)
-      typhoeus (~> 1.0)
-    cocoapods-deintegrate (1.0.5)
-    cocoapods-downloader (1.6.3)
-    cocoapods-plugins (1.0.0)
-      nap
-    cocoapods-search (1.0.1)
-    cocoapods-trunk (1.6.0)
-      nap (>= 0.8, < 2.0)
-      netrc (~> 0.11)
-    cocoapods-try (1.2.0)
-    colored2 (3.1.2)
-    concurrent-ruby (1.2.2)
-    escape (0.0.4)
-    ethon (0.15.0)
-      ffi (>= 1.15.0)
-    ffi (1.15.5)
-    fourflusher (2.3.1)
-    fuzzy_match (2.0.4)
-    gh_inspector (1.1.3)
-    httpclient (2.8.3)
-    i18n (1.14.1)
-      concurrent-ruby (~> 1.0)
-    json (2.6.1)
-    minitest (5.19.0)
-    molinillo (0.8.0)
-    nanaimo (0.3.0)
-    nap (1.1.0)
-    netrc (0.11.0)
-    public_suffix (4.0.6)
-    rexml (3.2.5)
-    ruby-macho (2.5.1)
-    typhoeus (1.4.0)
-      ethon (>= 0.9.0)
-    tzinfo (2.0.6)
-      concurrent-ruby (~> 1.0)
-    xcodeproj (1.21.0)
-      CFPropertyList (>= 2.3.3, < 4.0)
-      atomos (~> 0.1.3)
-      claide (>= 1.0.2, < 2.0)
-      colored2 (~> 3.1)
-      nanaimo (~> 0.3.0)
-      rexml (~> 3.2.4)
-    zeitwerk (2.6.11)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  cocoapods
-
-BUNDLED WITH
-   2.1.4