Describe the bug

The Dart SDK has migrated to a pub workspace, which should unblock lots of the IDE functionality that we were previously missing.

However when I tried it today whenever I try to run a test, I get " * The test run did not record any output. ".

To Reproduce
Steps to reproduce the behavior:

1. Open up the dart SDK (probably just a single package, such as pkg/dtd).
2. Open up a test (such as pkg/dtd/test/dart_tooling_daemon_test.dart)
3. Click the "play" button to the left of any given test/group

Expected behavior

It should run the test and show the result

Please complete the following information:

You can run the Dart: Collect Diagnostic Information command from the VS Code command palette (F1) to easily capture this information or provide it manually.

• Operating System and version:
• VS Code version:
• Dart extension version:
• Dart/Flutter SDK version:
  • latest master
• Target device (if the issue relates to Flutter debugging):