74764 [flutter_tools] handle further devtools NPE (cla: yes, tool)

74777 Replace MockXcode with Xcode.test in unit tests (cla: yes, platform-ios, team, tool, waiting for tree to go green)

74778 Rename setUpMockXcodeBuildHandler -> setUpFakeXcodeBuildHandler in tests (cla: yes, team, tool, waiting for tree to go green)

74780 Remove MockProcessManager from channel_test and other tests (cla: yes, team, tool)

74788 fix for upcoming lint use_named_constants (a: accessibility, a: tests, cla: yes, d: examples, f: cupertino, f: material design, framework, team, tool)

74817 [flutter_tools] remove mock from analyze_size_test.dart (cla: yes, tool, waiting for tree to go green)