In commit 8d16da14 (MDEV-24789)
we accidentally introduced a race condition. During the time a
waiting lock request is being removed, the request might be
moved to another page due to a concurrent page split or merge.
To prevent this, we must hold exclusive lock_sys.latch when releasing
a record lock.

lock_release_autoinc_locks(): Avoid a potential hang.
No dict_table_t::lock_mutex must be waited for while already holding
lock_sys.wait_mutex or trx_t::mutex.

lock_cancel_waiting_and_release(): Correctly handle AUTO_INCREMENT locks.