The InnoDB buffer pool and locking were heavily refactored in
MariaDB Server 10.6. Among other things, dict_sys.mutex was removed,
and the contended lock_sys.mutex was replaced with a combination of
lock_sys.latch and distributed latches in hash tables. Also, a
default value was changed to innodb_flush_method=O_DIRECT to improve
performance in write-heavy workloads.

One thing where an adjustment was missing is around the parameters
innodb_max_purge_lag (number of committed transactions waiting to
be purged), and innodb_max_purge_lag_delay
(maximum number of microseconds to delay a DML operation).

purge_coordinator_state::do_purge(): Pass the history_size to trx_purge()
and reset srv_dml_needed_delay if the history is empty.
Keep executing the loop non-stop as long as srv_dml_needed_delay is set.

trx_purge_dml_delay(): Made part of trx_purge().
Set srv_dml_needed_delay=0 when nothing can be purged (!n_pages_handled).

row_mysql_delay_if_needed(): Mimic the logic of
innodb_max_purge_lag_wait_update().

Reviewed by: Thirunarayanan Balathandayuthapani