Currently, concurrency sharded suites implicitly shard the default test collection 100% of the time. So in those suites, we only have test coverage for unsharded collections in tests that don't use the default test collection (e.g. set up per-thread collections). SERVER-90465 introduced the concept of TestData.shardCollectionProbability which allows suites to make the fsm runner not always shard the default test collection. TestData.shardCollectionProbability is currently only set in the config transition suites. We should consider setting in the regular suites to get more test coverage for unsharded collections.