Remove cirrus tests from the flutter framework. (#133575)

The flutter framework has been running tests both in luci and cirrus. We are removing Cirrus tests on favor of the LUCI ones.

.cirrus.yml

-# CIRRUS CONFIGURATION FILE
-# https://cirrus-ci.org/guide/writing-tasks/
-
-environment:
-  # For details about environment variables used in Cirrus, including how encrypted variables work,
-  # see https://cirrus-ci.org/guide/writing-tasks/#environment-variables
-  # We change Flutter's directory to include a space in its name (see $CIRRUS_WORKING_DIR) so that
-  # we constantly test path names with spaces in them. The FLUTTER_SDK_PATH_WITH_SPACE variable must
-  # therefore have a space in it.
-  FLUTTER_SDK_PATH_WITH_SPACE: "flutter sdk"
-  # We force BOT to true so that all our tools know we're in a CI environment. This avoids any
-  # dependency on precisely how Cirrus is detected by our tools.
-  BOT: "true"
-
-gcp_credentials: ENCRYPTED[!9409b709ab4de7293a70606cca13eaf42e9cbc704e8a6b4e3d2b09484cf997cbd2334e1eeafe23626ad07a726106df90!]
-
-# LINUX SHARDS
-task:
-  gke_container:
-    dockerfile: "dev/ci/docker_linux/Dockerfile"
-    builder_image_name: docker-builder-linux # gce vm image
-    builder_image_project: flutter-cirrus
-    cluster_name: test-cluster
-    zone: us-central1-a
-    namespace: default
-    cpu: $CPU
-    memory: $MEMORY
-    use_in_memory_disk: $USE_IN_MEMORY_DISK
-  environment:
-    # We shrink our default resource requirement as much as possible because that way we are more
-    # likely to get scheduled. We require 4G of RAM because most of the shards (all but one as of
-    # October 2019) just get OOM-killed with less. Some shards may need more. When increasing the
-    # requirements for select shards, please leave a comment on those shards saying when you
-    # increased the requirements, what numbers you tried, and what the results were.
-    CPU: 1 # 0.1-8 without compute credits, 0.1-30 with (yes, you can go fractional)
-    MEMORY: 4G # 256M-24G without compute credits, 256M-90G with
-    CIRRUS_WORKING_DIR: "/tmp/$FLUTTER_SDK_PATH_WITH_SPACE"
-    CIRRUS_DOCKER_CONTEXT: "dev/"
-    PATH: "$CIRRUS_WORKING_DIR/bin:$CIRRUS_WORKING_DIR/bin/cache/dart-sdk/bin:$PATH"
-    ANDROID_SDK_ROOT: "/opt/android_sdk"
-    SHOULD_UPDATE_PACKAGES: 'TRUE' # can be overridden at the task level
-    USE_IN_MEMORY_DISK: false
-  pub_cache:
-    folder: $HOME/.pub-cache
-    fingerprint_script: echo $OS; grep -r --include=pubspec.yaml 'PUBSPEC CHECKSUM' "$CIRRUS_WORKING_DIR"
-    reupload_on_changes: false
-  flutter_pkg_cache:
-    folder: bin/cache/pkg
-    fingerprint_script: echo $OS; cat bin/internal/*.version
-    reupload_on_changes: false
-  artifacts_cache:
-    folder: bin/cache/artifacts
-    fingerprint_script: echo $OS; cat bin/internal/*.version
-    reupload_on_changes: false
-  setup_script:
-    - date
-    - git clean -xffd --exclude=bin/cache/
-    - git fetch origin
-    - git fetch origin master # To set FETCH_HEAD, so that "git merge-base" works.
-    - flutter config --no-analytics
-    - if [ "$SHOULD_UPDATE_PACKAGES" == TRUE ]; then flutter update-packages; fi
-    - flutter doctor -v
-    - ./dev/bots/accept_android_sdk_licenses.sh
-    - date
-  on_failure:
-    failure_script:
-      - date
-      - which flutter
-  matrix:
-    - name: analyze-linux # linux-only
-      only_if: "$CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # Empirically, the analyze-linux shard runs surprisingly fast (under 15 minutes) with just 1
-        # CPU.  We noticed OOM failures with 6GB 4/2020, so we increased the memory.
-        CPU: 1
-        MEMORY: 8G
-      script:
-        - dart --enable-asserts ./dev/bots/analyze.dart
-
-    - name: framework_tests-widgets-linux
-      only_if: "changesInclude('.cirrus.yml', 'dev/**', 'packages/flutter/**', 'packages/flutter_test/**', 'packages/flutter_tools/lib/src/test/**', 'bin/**') && $CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # We use 3 CPUs because that's the minimum required to get framework_tests-widgets-linux
-        # running fast enough that it is not the long pole, as of October 2019.
-        CPU: 3
-      script:
-        - dart --enable-asserts ./dev/bots/test.dart
-
-    - name: framework_tests-libraries-linux
-      only_if: "changesInclude('.cirrus.yml', 'dev/**', 'packages/flutter/**', 'packages/flutter_test/**', 'packages/flutter_tools/lib/src/test/**', 'bin/**') && $CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # We use 3 CPUs because that's the minimum required to get the
-        # framework_tests-libraries-linux shard running fast enough that it is not the long pole, as
-        # of October 2019.
-        CPU: 3
-      script:
-        - dart --enable-asserts ./dev/bots/test.dart
-
-    - name: framework_tests-misc-linux
-      # this includes the tests for directories in dev/
-      only_if: "changesInclude('.cirrus.yml', 'dev/**', 'packages/flutter/**', 'packages/flutter_goldens/**', 'packages/flutter_test/**', 'packages/flutter_tools/lib/src/test/**', 'bin/**') && $CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # We use 3 CPUs because that's the minimum required to get framework_tests-misc-linux
-        # running fast enough that it is not the long pole, as of October 2019.
-        CPU: 3
-      script:
-        - dart --enable-asserts ./dev/bots/test.dart
-
-    - name: tool_tests-general-linux
-      only_if: "changesInclude('.cirrus.yml', 'dev/**', 'packages/flutter_tools/**', 'bin/**') && $CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # As of November 2019, the tool_tests-general-linux shard got faster with more CPUs up to 4
-        # CPUs, and needed at least 10G of RAM to not run out of memory.
-        CPU: 4
-        MEMORY: 10G
-        SHOULD_UPDATE_PACKAGES: "FALSE"
-      script:
-        - (cd packages/flutter_tools; dart pub get)
-        - (cd packages/flutter_tools/test/data/asset_test/main; dart pub get)
-        - (cd packages/flutter_tools/test/data/asset_test/font; dart pub get)
-        - (cd dev/bots; dart pub get)
-        - dart --enable-asserts ./dev/bots/test.dart
-
-    - name: tool_tests-commands-linux
-      only_if: "changesInclude('.cirrus.yml', 'dev/**', 'packages/flutter_tools/**', 'bin/**') && $CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # As of October 2019, the tool_tests-commands-linux shard got faster with more CPUs up to 6
-        # CPUs, and needed at least 8G of RAM to not run out of memory.
-        # Increased to 10GB on 19th Nov 2019 due to significant number of OOMKilled failures on PR builds.
-        CPU: 6
-        MEMORY: 10G
-        SHOULD_UPDATE_PACKAGES: "FALSE"
-      script:
-        - (cd packages/flutter_tools; dart pub get)
-        - (cd dev/bots; dart pub get)
-        - dart --enable-asserts ./dev/bots/test.dart
-
-    - name: docs-linux # linux-only
-      environment:
-        CPU: 4
-        MEMORY: 12G
-      only_if: "$CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      script:
-        - ./dev/bots/docs.sh
-
-    - name: customer_testing-linux
-      only_if: "$CIRRUS_PR != '' && $CIRRUS_BASE_BRANCH == 'master'"
-      environment:
-        # Empirically, this shard runs fine at 1 CPU and 4G RAM as of October 2019. We will probably
-        # want to grow this container when we invite people to add their tests in large numbers.
-        SHOULD_UPDATE_PACKAGES: "FALSE"
-      script:
-        # Cirrus doesn't give us the master branch, so we have to fetch it for ourselves,
-        # otherwise we won't be able to figure out how old or new our current branch is.
-        - git config user.email "cirrus-bot@invalid"
-        - git fetch origin master:master
-        # The actual logic is in a shell script so that it can be shared between CIs.
-        - (cd dev/customer_testing/; ./ci.sh)