MySQL connector should apply database and table filters to system dbs/tables

Currently, the MySQL connector ignores built-in tables by default, but the table.ignore.builtin property can be set to false to change that behavior. However, in the latter case the user-supplied table and database filters are not applied to the built-in tables, meaning all of the built-in tables will be included. See this code for details.

This behavior is not correct, and the database and table filters should always be applied to all tables; the table.ignore.builtin should just control whether or not they are automatically excluded without having to do so in the filters.