quick_rm_table() expects .frm to exist when it removes high-level indexes.
For cases like ALTER TABLE t1 RENAME TO t2, ENGINE=other_engine .frm was
removed earlier.

Another option would be removing high-level indexes explicitly before the
first quick_rm_table() and skipping high-level indexes for subsequent
quick_rm_table(NO_FRM_RENAME).

But this suggested order may also help with ddl log recovery. That is
if we crash before high-level indexes are removed, .frm is going to
exist.