41251 Migrate examples and tests to AndroidX (a: accessibility, cla: yes, d: examples, team, team: gallery)

41254 Test that flutter assets are contained in the APK (cla: yes, team)

41263 fix bad indentation (cla: yes, framework, team)

41295 Revert “Re-Re-land Implement flutter build bundle with assemble” (cla: yes, team, tool)

41300 Modifying unit tests for editable_text (cla: yes, framework)

41302 Re-Re-Re-land implement flutter build bundle with assemble (cla: yes, team, tool)

41304 [flutter_tools] Allows adding multiple signal handlers (cla: yes, tool)