[flutter_releases] Flutter Beta 2.2.0-10.3.pre Engine Cherrypicks

[christopherfujino]

Scheduled Cherrypicks

• 1 Dart CP dart-lang/sdk@4511eb2
• #76097 platformview doesn't correctly clip in scrollview on iOS
  • 72114da
  • Original author @flar

Infra-only Cherrypicks

• Roll buildroot to pick up:
  • Make cppwinrt check SDK/References folder if using standard sdk location failed. buildroot#447
• Add expat to DEPS cp of Migrate third_party/expat dependency to googlecode #25683

Known Presubmit Failures

• Linux Android AOT Engine - failure during scenario_app testing expecting file not built by this release branch https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket.appspot.com/8847867331991637840/+/u/Firebase_test/stdout
• Linux Web Framework tests - upstream framework changes not supported by this release branch
• build_and_test_linux_unopt_debug - upstream framework changes not supported by this release branch

This release was delayed by a general Flutter CI outage flutter/flutter#81837

[flutter-dashboard]

This pull request was opened from and to a release candidate branch. This should only be done as part of the official Flutter release process. If you are attempting to make a regular contribution to the Flutter project, please close this PR and follow the instructions at Tree Hygiene for detailed instructions on contributing to Flutter.

Reviewers: Use caution before merging pull requests to release branches. Ensure the proper procedure has been followed.

[kf6gpe]

LGTM.