Support multiple-table syntax of DELETE statement

[JanVoracek]

Docs: https://dev.mysql.com/doc/refman/8.0/en/delete.html#idm140219041342912

There are two possible forms of multiple-table delete statement (queries based on this tutorial):

• DELETE t1, t2 FROM t1 INNER JOIN t2 ON t2.ref = t1.id WHERE t1.id = 1
• DELETE FROM t1, t2 USING t1 INNER JOIN t2 ON t2.ref = t1.id WHERE t1.id = 1;

Looks like the former one is supported but the latter one is not – it ends up with two ParseExceptions.