[infra] Remove AST builders from the test matrix
[infra] Remove AST builders from the test matrix

These builders were already removed from the Luci config:
https://dart-review.googlesource.com/c/sdk/+/127645

Change-Id: I59a96d7ea0a042d41e265648753bc594833550fe
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/128064
Auto-Submit: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>
Reviewed-by: Siva Annamalai <2e618a8cbd7bb6b3d4409061ae407d692a098546@google.com>

dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk