SOLR-3622, SOLR-5847, SOLR-6194, SOLR-6269: Several DIH fixes/improvements (merged from r1613406)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1613409 13f79535-47bb-0310-9956-ffa450edef68