DERBY-6357: CREATE TRIGGER doesn't detect all illegal references to SESSION schema

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1527963 13f79535-47bb-0310-9956-ffa450edef68
DERBY-534: Support use of the WHEN clause in CREATE TRIGGER statements

Disallow references to tables in the SESSION schema in the WHEN clause.

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1527993 13f79535-47bb-0310-9956-ffa450edef68