21952 Roll Dart SDK from 675c7165c071 to 5c59a47beda7 (1 revision) (cla: yes, waiting for tree to go green)

21953 Restore missing call to RuntimeDelegate.OnRootIsolateCreated (cla: yes)

21955 Roll Fuchsia Mac SDK from 9mMCqUXkF… to MR_bRfe8I… (cla: yes, waiting for tree to go green)

21956 Roll Skia from be8004d2fb6c to 27f7fe32f49b (1 revision) (cla: yes, waiting for tree to go green)

21959 [null-safety] fix return type of some pushLayer native bindings (cla: yes)