21987 [iOS] Fixes leaks of presses key message (cla: yes, platform-ios)

22016 Reland [ios] Refactor IOSSurface factory and unify surface creation (cla: yes, platform-ios, waiting for tree to go green)

22082 [ios] Convert FlutterPlatformViewsController to smart pointer (cla: yes, platform-ios)

22170 [profiling] Handle thread_info to account for killed threads (cla: yes, platform-ios)

22171 [flutter_releases] Flutter 1.22.3 engine cherrypicks (cla: yes, platform-android, platform-ios)

22179 Split AOT Android Embedder and shell (cla: yes, platform-android, platform-ios, waiting for tree to go green)