Handle temporary tables like permanent tables: If the storage engine
cannot truncate, delete instead.


mysql-test/r/innodb.result:
  Bug#11816 - Truncate table doesn't work with temporary innodb tables
  The test result.
mysql-test/t/innodb.test:
  Bug#11816 - Truncate table doesn't work with temporary innodb tables
  The test case.
sql/sql_delete.cc:
  Bug#11816 - Truncate table doesn't work with temporary innodb tables
  Handle temporary tables like permanent tables: If the storage engine
  cannot truncate, delete instead.
  Replaced a numeric literal by its symbolic name.