Partial revert of this commit:

  commit 6b685ea7
  Author: Sergei Golubchik <serg@mariadb.org>
  Date:   Wed Sep 28 18:55:15 2022 +0200

Don't hold LOCK_thd_data over run_commit_ordered(). Holding the mutex
is unnecessary and will deadlock if any code in a commit_ordered
handlerton call tries to take the mutex to change THD local data.

Instead, set the current_thd for the duration of the call to keep
asserts happy around LOCK_thd_data.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>