52532 Move flutter_gallery to the testing folder (a: accessibility, cla: yes, d: examples, f: cupertino, f: material design, team, team: gallery, tool)

52534 Roll engine d7a00b8b09b0..f746b01c402e (1 commits) (cla: yes, waiting for tree to go green)

52539 Roll engine f746b01c402e..af426986b337 (1 commits) (cla: yes, waiting for tree to go green)

52542 [flutter_tools]: reland android device cleanup (cla: yes, tool)

52543 [flutter_tools]: reland move engine unpack to dart (cla: yes, tool)

52547 Make AnimatedSwitcher example into a dartpad example (cla: yes, framework)