Problem was that we used table->s->db_type() for accessing
handlerton of opened file instead of table->file->ht
Other bug fixed:
- Ensure that we set error if reopen_tables() fails
(This was the cause of assert)
MDEV-14831 CREATE OR REPLACE SEQUENCE under LOCK TABLE corrupts the
sequence, causes ER_KEY_NOT_FOUND
The problem was that sequence_insert didn't properly handle the case
where there where there was a LOCK TABLE while creating the sequence.
Fixed by opening the sequence table, for inserting the first record, in
a new environment without any other open tables.
Found also a bug in Locked_tables_list::reopen_tables() where the lock
structure for the new tables was allocated in THD::mem_root, which causes
crashes. This could cause problems with other create tables done under
LOCK TABLES.