70424 Cherry pick - Flutter 1.24 candidate.11 (a: accessibility, a: tests, cla: yes, framework, team)

70447 fix some unit test cases(ink_well_test.dart) bug (cla: yes, f: material design, framework)

70469 Enable test after engine fix (cla: yes, framework, waiting for tree to go green)

70487 Ignore text selection boxes when assembling semantics for placeholder runs (cla: yes, framework, waiting for tree to go green)

70491 Remove some unnecessary casts, now that changes have rolled from the engine (a: internationalization, a: tests, cla: yes, framework, waiting for tree to go green)

70500 More lints (a: accessibility, a: internationalization, a: tests, cla: yes, f: cupertino, framework, team)