zuul: skip test/test-prio for CR+2 changes
When doing a 'recheck', the 'comment-added' event caries the change
approval and it thus enter both test and gate-and-submit pipeline.
To prevent test/test-prio from enqueuing in such a case, have them
reject changes that have a CR+2 approval.
The reject: is available in Zuul since:
Add tests to:
- verify gate-and-submit accepts a comment carrying a CR+2, done by having the event to carry the change approvals.
- for independrent pipelines reacting to 'recheck', make sure they:
- reject changes that received a Code-Review +2
- accept changes without approvals which requires upstream patch https://review.opendev.org/#/c/589762/ Or Id2505e3823bd9badabb3e33103cbe537be36701d