9590 Apply patches that have landed in topaz since we ported the runners to the engine repo (cla: yes)

9591 Document various classes in //flutter/shell/common. (cla: yes)

9593 [trace clients] Remove fuchsia.tracelink.Registry (cla: yes)

9608 Disable failing Mutators tests (cla: yes)

9613 Fix uninitialized variables and put tests in flutter namespace. (cla: yes)

9632 Added Doxyfile. (cla: yes)

9633 Cherry-pick fix for flutter/flutter#35291 (cla: yes)

9634 Roll Dart to 67ab3be10d35d994641da167cc806f20a7ffa679 (cla: yes)