20236 Revert “Add preliminary Windows arm64 plumbing” (cla: yes)

20237 reducing the shard number to 8 for framework tests (cla: yes)

20238 1.20 CP: fix FlutterViewUpdateCustomAccessibilityActions uses correct string list (cla: yes, platform-android)

20241 Remove unnecessary breaks after returns in lib/web_ui switch statements (cla: yes)

20243 Reland “Add preliminary Windows arm64 plumbing” (cla: yes)

20245 Add FlutterFragmentActivity#getRenderMode() (cla: yes, platform-android, waiting for tree to go green)

20247 Switched the linter to use the dart that comes with the engine. (cla: yes)