LUCENE-5904: fix test to make empty initial commit

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1621422 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5904: fix redundant cast warning

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1621423 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5904: fix false fail

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1621429 13f79535-47bb-0310-9956-ffa450edef68
don't let virus checker run when testing merge stability

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1621432 13f79535-47bb-0310-9956-ffa450edef68