1003: Incorrect table name
in multi-table DELETE the set of tables to delete from actually 
references then tables in the other list, e.g:
DELETE alias_of_t1 FROM t1 alias_of_t1 WHERE ....
is a valid statement.
So we must turn off table name syntactical validity check for alias_of_t1 
because it's not a table name (even if it looks like one).
In order to do that we add a special flag (TL_OPTION_ALIAS) to 
disable the name checking for the aliases in multi-table DELETE.