Run mysql tests on stable preperation branches like 9-3-stable-patch-2
What
Runs mysql tests on branches such as 9-3-stable-patch-2
instead of just ones ending with stable
Follows on from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11602#note_30326598
Why
We've started using preparation MRs to get things working before commits land on stable. This means mysql tests now need to run on branches which don't end in stable.
Edited by James Edwards-Jones