Add a retry_count option for test Statements

A medium sized hammer for working around vulnerable statements, which include DROP and UPDATE_STATISTICS fighting the background statistics updater.

This isn't generally an issue in ITs as background updating is effectively disabled due to TestConfigService#testing() returning true. For my local testing, I flipped that to false and saw issues very similar to FTS. Those are fixed by this branch.

We may want to generalize Store#isRetryable() and make use of that in YamlTester, but it's about 3 steps removed at this point.