Fix regress_29025_test
Fix regress_29025_test

This test doesn't do what it once did since callable classes are no
longer function subtypes. Still, we can preserve some of the behavior.

Change-Id: I92f503bfbbe81685cf79a3bb9b6d85b6859d3c52
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/116141
Auto-Submit: Mayank Patke <e0355b78204b67a55a952941c68c8f1b40235938@google.com>
Reviewed-by: Bob Nystrom <afede3a9ebedb865bee78398feff6fbe97068f17@google.com>
Commit-Queue: Mayank Patke <e0355b78204b67a55a952941c68c8f1b40235938@google.com>

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