Fixes#47303
GetQueryResultsCounts and IncrQueryResultsCounts pipelined commands
across multiple query_results_count:<id> keys on a single connection.
These keys have no hash tag, so in a Redis Cluster they scatter across
hash slots. A pipelined connection binds to the first key's slot, so
every other key returned a MOVED redirect, producing recurring error log
noise on host check-ins. IncrQueryResultsCounts additionally used
ConfigureDoer, whose RetryConn does not support Send, so increments
failed entirely in cluster mode.
Group the keys by hash slot with redis.SplitKeysBySlot and run one
pipeline per slot group, mirroring the existing QueriesForHost and
CleanupInactiveQueries patterns in the same file. The write path uses a
plain pooled connection (not ConfigureDoer) since all keys in a slot
group share a slot and no redirect handling is needed.
Juan Fernandez
013718aacb