The cardinality_and_frequency.js test may time out in sharded_collections_jscore_passthrough_rate_limited suite. The suite inherits implicitly_shard_accessed_collections.js, which auto-shards empty collections on {_id: "hashed"}. The test needs to control shard keys and supporting indexes for analyzeShardKey cardinality/frequency metrics. Accessing collections via getCollection already shards them, so later shardCollection / unique-index setup hits AlreadyInitialized or CannotCreateIndex. The test skips those cases and continues; under rate limiting the skip loop burns the timeout.
As part of this ticket we need to add assumes_unsharded_collection  so the rate-limited suite will stop selecting the test.