Remove unused files (#63532)

dev/bots/download_android_sdk.sh

-#!/usr/bin/env bash
-# Copyright 2014 The Flutter Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-set -e
-
-if [[ -z $ANDROID_SDK_TOOLS_URL || -z $ANDROID_HOME || -z $ANDROID_SDK_ROOT ]]; then
-  exit 0
-fi
-
-curl -L $ANDROID_SDK_TOOLS_URL --output android_sdk_tools.zip
-
-mkdir -p $ANDROID_SDK_ROOT
-unzip android_sdk_tools.zip -d $ANDROID_SDK_ROOT
-rm android_sdk_tools.zip
-
-yes | $ANDROID_SDK_ROOT/tools/bin/sdkmanager --licenses
-$ANDROID_SDK_ROOT/tools/bin/sdkmanager tools
-$ANDROID_SDK_ROOT/tools/bin/sdkmanager platform-tools
-# this is large and we don't need it just yet
-# $ANDROID_SDK_ROOT/tools/bin/sdkmanager emulator
-$ANDROID_SDK_ROOT/tools/bin/sdkmanager  "platforms;android-28" \
-    "build-tools;28.0.3" \
-    "platforms;android-27" \
-    "build-tools;27.0.3" \
-    "extras;google;m2repository" \
-    "extras;android;m2repository"

dev/bots/download_open_jdk.sh

-#!/usr/bin/env bash
-# Copyright 2014 The Flutter Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-set -e
-
-if [[ -z $OPEN_JDK_URL ]]; then
-  exit 0
-fi
-
-mkdir -p $HOME/Java
-pushd $HOME/Java
-curl -L $OPEN_JDK_URL --output open_jdk.tar.gz
-tar -xvf open_jdk.tar.gz
-rm open_jdk.tar.gz
-popd