Dropping Migrate tables
Please test these thoroughly and/or export the list of tables to drop to a list then write a tidy update hook rather than blowing away data you didn't mean to.
It's a safer idea to write an update hook or export a list of tables to target because it may not be a fair assumption that every table named
migrate_* is one you can delete without impact. That's why the core functionality proposed uses a scan for known migrations rather than just deleting tables based on a pattern match.
That said, here are some quick solutions: