SOLR-6718: coreRootDirectory should be resolved against SOLR_HOME

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1646660 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-6118: Improve the efficiency of the history structure for recently-used filters.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1646674 13f79535-47bb-0310-9956-ffa450edef68