LUCENE-5077: make it easier to use compressed norms

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1496476 13f79535-47bb-0310-9956-ffa450edef68
SOLR-4948: Tidy up CoreContainer construction logic

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1496505 13f79535-47bb-0310-9956-ffa450edef68