68128 [flutter_tools] partial revert of start app change (cla: yes, tool)

68129 Convert some more widget tests to NNBD (cla: yes, framework)

68131 [flutter_tools] ensure android log reader works in flutter drive (cla: yes, tool)

68132 Update package:stack_trace dependency to 1.10.0-nullsafety.4 (cla: yes, team, tool)

68133 Migrate Switch tests to null safety. (cla: yes, f: material design, framework, waiting for tree to go green)

68135 [flutter_releases] Flutter 1.22.2 framework cherrypicks (a: tests, cla: yes, engine, f: cupertino, f: material design, framework, team, tool)