28923 [fuchsia] Dart Runner for CF v2 components. (cla: yes, platform-fuchsia, needs tests)

28924 [Linux, Embedder] Add engine restart hooks (cla: yes, platform-linux, embedder)

28925 made android unit tests not require the host engine variant to exist (cla: yes, waiting for tree to go green)

28926 fuchsia: Add FakeFlatland and tests (affects: tests, cla: yes, platform-fuchsia)

28930 [ci.yaml] add main references (cla: yes)

28931 Update builder configs. (cla: yes)

28932 Roll Fuchsia Mac SDK from Lx_DI2yrc… to owSIykHxQ… (cla: yes, waiting for tree to go green)