This is a 10.3 specific part of MDEV-13049.
It disables automatic sorting for
"SELECT .. FROM INFORMATION_SCHEMA.{SCHEMATA|TABLES}"
and adjusts the affected tests accordingly.
Early evaluation of subqueries in the WHERE conditions on I_S.*_STATUS tables,
otherwise the subquery on this same table will try to acquire LOCK_status twice.
sql/item.h:
remove unused method