SOLR-6370: Allow tests to report/fail on many ZK watches being parallelly requested on the same data (This closes #84)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1626253 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5936: Tweak test to isolate trunk only code

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1626258 13f79535-47bb-0310-9956-ffa450edef68