rocksdb.lock: LOCK TABLE t1 LOW_PRIORITY WRITE does not produce a
  warining in MariaDB

rocksdb.unique_check:
- MariaDB's mtr prints connection actions
- New (but temporary) ER_LOCK_WAIT_TIMEOUT text

rocksdb.allow_pk_no_concurrent_insert:
- Fix path

rocksdb.locking_issues
- Fix path
- The test still fails but for a different reason now