LUCENE-5993: Remove DocIdBitSet, WAH8DocIdSet and PForDeltaDocIdSet.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1629921 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5996: Collections.shuffle(List) is now a forbidden API.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1629922 13f79535-47bb-0310-9956-ffa450edef68
SOLR-6589: Test is fixed by the commit in SOLR-6590

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1629924 13f79535-47bb-0310-9956-ffa450edef68