Merged revision(s) 1518839 from lucene/dev/trunk:
LUCENE-5191: Fix Unicode corrumption in HTML escaping of Standard Highlighter and Fast Vector Highlighter.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1518840 13f79535-47bb-0310-9956-ffa450edef68