OAK-1273: Reduce overhead when handling many parallel property indices

Avoid duplicate VisibleEditor wrapping of index editors.
Only the IndexUpdate class should use the VisibleEditor to wrap index editors

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1550315 13f79535-47bb-0310-9956-ffa450edef68