No need to track allocations of bNodes when using a policy
that uses the label to create the AnonId.  Removed memory
consumption by the map at scale.  Precursor for JENA-352.

Other misc cleanups in passing.


git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1460886 13f79535-47bb-0310-9956-ffa450edef68