Roll recipe dependencies (trivial).

This is an automated CL created by the recipe roller. This CL rolls recipe
changes from upstream projects (build, fuchsia) into this repository.

build:
  https://crrev.com/e440f5686478a1ac483af636a9c25f94a367546b (gbeaty@chromium.org)
    Update chromium_libfuzzer recipes to refer to builder groups.
fuchsia:
  https://crrev.com/19876c30fdb87e0f26f7d926debd95261572b478 (atyfto@google.com)
    [fuchsia/fuchsia] Skip external tests if build graph was unaffected
  https://crrev.com/2b21dc738622bfc7d2bc8af63c5cc60d9bd947de (mcgrathr@google.com)
    [gcc_toolchain] Use api.macos_sdk() only once

More info is at https://goo.gl/zkKdpD. Use https://goo.gl/noib3a to file a bug.

TBR=keyonghan@google.com

Recipe-Tryjob-Bypass-Reason: Autoroller
Bugdroid-Send-Email: False
Change-Id: I9d8a64ff017616826c3660ceaac3f9480ce65d69
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/5720
Reviewed-by: flutter-prod-builder@chops-service-accounts.iam.gserviceaccount.com <flutter-prod-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: flutter-prod-builder@chops-service-accounts.iam.gserviceaccount.com <flutter-prod-builder@chops-service-accounts.iam.gserviceaccount.com>