DERBY-3155: Add tests to verify that BEFORE triggers can't fire MERGE statements, just as they can't fire INSERT/UPDATE/DELETE statements; commit derby-3155-11-ab-beforeTriggersCantFireMerge.diff.

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1549948 13f79535-47bb-0310-9956-ffa450edef68