Extend testing infrastructure to handle expected intermittent flaky tests - see ReplicationAwareTokenAllocatorTest.testNewCluster

From an offline discussion:

The ReplicationAwareTokenAllocatorTest.testNewCluster failure is a flake – randomness will sometimes (on the order of 1/100) cause it to fail. Extending the ranges to avoid these flakes goes too far and makes the test meaningless.

How about instead of @flaky/@Ignore which currently indicates a test that intermittently fails but we do not expect it to, we instead use @tries, or @runs, or some annotation that indicates "run this thing N times, if M pass we're good". This would allow us to keep the current "we don't care about these test results (in context of green test board) because intermittent failures are not expected and the test quality needs shoring up" from "we expect this test to fail sometimes in this particular way."