fix test to not create such a big automaton

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1637450 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-6054: allow repeating the empty automaton

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_5x@1637452 13f79535-47bb-0310-9956-ffa450edef68