27353 [fuchsia] Use FFI to get System clockMonotonic (cla: yes, waiting for tree to go green, platform-fuchsia, needs tests)

27364 Revert “NNBD migration for scenario_app” (cla: yes, needs tests)

27365 Scenario nnbd (cla: yes, needs tests)

27367 Fix dart analysis (cla: yes, waiting for tree to go green, needs tests)

27377 [fuchsia] fix race in DefaultSessionConnection (cla: yes, platform-fuchsia, needs tests)

27401 remove the use of package:isolate (cla: yes, needs tests)

27433 fuchsia: Log vsync stats in inspect (cla: yes, platform-fuchsia, needs tests)