Reduce the complexity of some contributed Conditions tests.

Review Request #10358 — Created Dec. 13, 2018 and submitted — Latest diff uploaded

Review Board

We recently had a contribution that added some new condition choices for
reviewers and participants in reviews. These introduced some very
extensive tests, which were more extensive than were needed for the
functionality, and got in the way of some upcoming work for optimizing
participants. It was also just a bit hard to truly see what was being
tested, given how much was going on.

This change simplifies these tests, reducing them to test the specific
behavior that matters in a more readable fashion.

Unit tests pass.