[infra] Add custom test runner support to approve_results
[infra] Add custom test runner support to approve_results

This should fix vm-dartkb-linux-release-x64-abi.

Change-Id: I5e7b8e355416669f0bc3ed3e94fdff3c616293c9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/107288
Auto-Submit: Alexander Thomas <29642742b6693024c89de8232f2e2542cf7eedf7@google.com>
Reviewed-by: Jonas Termansen <092ec58085ae5e368bc39d18752740ff81a2d09c@google.com>

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