DERBY-6383(Update trigger defined on one column fires on update of other columns)

Backporting following 2 revisions from trunk to 10.10. Had to hand do the changes because of conflicts during svn merge.
1537593, 1538854 



git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.10@1539074 13f79535-47bb-0310-9956-ffa450edef68