7213 Roll Dart to version e15e8609aa8610f8c432f1caf2ab89358e2fce50 (cla: yes)

7214 [Fuchsia] Depend on libtrace when that is what’s really meant (cla: yes)

7221 [vulkan] Fix Fuchsia build (cla: yes)

7227 Compile embedder unit test Dart to kernel (cla: yes)

7230 Revert “Compile embedder unit test Dart to kernel (#7227)” (cla: yes)

7231 Compile embedder unit test Dart to kernel (re-land) (cla: yes)

7234 Fix misspelling in doc comments (cla: yes)