Aria checks skip_external_locking

Aria still checks my_disable_locking (which corresponds to the skip_external_locking system variable) in a few cases.

https://github.com/MariaDB/server/blob/mariadb-10.4.4/sql/sys_vars.cc#L2845

Is this intentional, or an oversight that is still leftover from MyISAM?

For example, it checks it when checking if a table has crashed:

https://github.com/MariaDB/server/blob/mariadb-10.4.4/storage/maria/ha_maria.cc#L2376

And when opening a table:

https://github.com/MariaDB/server/blob/mariadb-10.4.4/storage/maria/ma_open.c#L458

And when decrementing the table's open count:

https://github.com/MariaDB/server/blob/mariadb-10.4.4/storage/maria/ma_locking.c#L516

In contrast, it looks like it grabs a mutex when incrementing this count:

https://github.com/MariaDB/server/blob/mariadb-10.4.4/storage/maria/ma_locking.c#L427