50160 Reland: Skia gold driver test (a: tests, cla: yes, framework, team)

50166 Web benchmarks: make headless mode opt-out (cla: yes, team)

50178 unnecessary escapes fixes (cla: yes, d: examples, team, team: gallery, tool, waiting for tree to go green)

50180 Added parallax effect for cupertino fullscreenDialog (a: fidelity, cla: yes, f: cupertino, framework, waiting for tree to go green)

50200 [flutter_tools] Reland migrate xcode_backend.sh to flutter assemble (cla: yes, tool)

50213 Remove android directory from platform_channel_swift example project (cla: yes, d: examples, team, waiting for tree to go green)