MDEV-5723: mysqldump -uroot unusable for multi-database operations, checks all databases - MariaDB-5.5 part of the fix: since we can't easily fix query optimization for I_S tables,    run the affected-tablespaces query with semijoin=off. It happens to have a good query plan   with that setting.
MDEV-5723: mysqldump -uroot unusable for multi-database operations, checks all databases
- MariaDB-5.5 part of the fix: since we can't easily fix query optimization for I_S tables, 
  run the affected-tablespaces query with semijoin=off. It happens to have a good query plan
  with that setting.

davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,slanterns/server,natsys/mariadb_10.2,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,ollie314/server,ollie314/server,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,ollie314/server,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2