DERBY-6751: Improve performance of ResultSet.next() by caching the lcc in ConnectionChild; tests passed cleanly on derby-6751-02-ab-cacheLCC.diff.

git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1629866 13f79535-47bb-0310-9956-ffa450edef68