67361 Characters docs (cla: yes, f: cupertino, f: material design, framework, team, waiting for tree to go green)

67363 Remove measureIosCpuGpu (cla: yes, team, waiting for tree to go green)

67364 Make FlutterErrorDetails.exception non-nullable as documented (cla: yes, framework, waiting for tree to go green)

67367 Remove the .zip method from OSUtils, as it was not used (cla: yes, tool)

67369 [flutter_tools] work around hostonly test (cla: yes, tool)

67375 Add rootOverlay flag to [Draggable], to put feedback on root [Overlay] (cla: yes, framework)