LUCENE-4733: Refactor term vectors formats tests around a BaseTermVectorsFormatTestCase.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1441367 13f79535-47bb-0310-9956-ffa450edef68
Fix test bug (used to rely on internal doc IDs).


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1441395 13f79535-47bb-0310-9956-ffa450edef68
Merged /lucene/dev/trunk:r1441297-1441422

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene4547@1441423 13f79535-47bb-0310-9956-ffa450edef68