Shenandoah repository uses GHA tests:
  https://github.com/openjdk/shenandoah

They used to run the tests in the "openjdk" context, but that is gone, and the tests would now run in the personal forks. The configuration step is needed in Skara bots to use the results from the GHA test builds as PR checks so they can be reported in pull requests.

This is similar to SKARA-1124, SKARA-1132, SKARA-1413, SKARA-1869, etc.