This is a regression due to MDEV-16515 that affects some versions in
the MariaDB 10.1 server series starting with 10.1.35, and possibly
all versions starting with 10.2.17, 10.3.8, and 10.4.0.

The idea of MDEV-16515 is to allow DROP TABLE to be interrupted,
in case it was stuck due to some concurrent activity. We already
made some cases of internal DROP TABLE immune to kill in MDEV-18237,
MDEV-16647, MDEV-17470. We must include the cleanup of
CREATE TABLE...SELECT in the list of such internal DROP TABLE.

ha_innobase::delete_table(): Pass create_failed=true if the current
SQL statement is CREATE, so that the table will be dropped.

row_drop_table_for_mysql(): If create_failed=true, do not allow
the operation to be interrupted.