10240 [fuchsia] Update buildroot to support arm64 (cla: yes)

10242 Remove Dead Scenic Clipping Code Path. (cla: yes)

10246 [fuchsia] Start building dart_patched_sdk (cla: yes)

10250 Android Embedding Refactor 38: Removed AssetManager from DartEntrypoint. (cla: yes)

10260 [fuchsia] Add arm64 builds for flutter and dart runner (cla: yes)

10261 [fuchsia] Bundle architecture specific gen_snapshots (cla: yes)

10265 [dart-roll] Roll dart sdk to 80c4954d4d1d2a257005793d83b601f3ff2997a2 (cla: yes)