Prevent intermittent failures in RepoIndexerTest (#19225 #19229) (#19228)
Backport #19225
Backport #19229
The RepoIndexerTest is failing with considerable frequency due to a race inherrent in
its design. This PR adjust this test to avoid the reliance on waiting for the populate
repo indexer to run and forcibly adds the repo to the queue. It then flushes the queue.
It may be worth separating out the tests somewhat by testing the Index function
directly away from the queue however, this forceful method should solve the current
problem.