LUCENE-4571: fix rare test bug and beef up matching tests some more

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1459820 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-4571: also verify scores in this test

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1459842 13f79535-47bb-0310-9956-ffa450edef68