safety first - tell mariadb client not to execute dangerous
cli commands, they cannot be present in the dump anyway.
wrapping the command in /*!999999 ..... */ guarantees that
if a non-mariadb-cli client loads the dump and sends it to the
server - the server will ignore the command it doesn't understand
With a global non-default max-statement-time of a time interval that exceed
the query time mysqldump queries when doing a backup.
To solve both, add a max-statement-time option, defaulting to 0 (unlimited time).
Also like mariabackup, set the session wait_timeout=DEFAULT (28800). The
time/processing between mysqldump times isn't expected to get that
close ever, but let's adopt the standard of mariabackup as no-one has
challenged it has having a detrimental effect.
Reviewer and test case author Daniel Black
