- Pre-open temporary table on sequence creation.
- Without this patch, if rename alter is done on the temporary sequence,
  and after that `create replace`, since table is not preopened and
  alter rename marked the table as reopen, and such table is deleted in
  the `find_temporary_table()` leaving the share without the table, that
  causes `show tables` to fail
- Closes PR #2685
- Reviewer: <serg@mariadb.com>