LUCENE-5675: more rote factoring

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene5675@1595020 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5675: break out SegmentTermsEnum.Frame

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene5675@1595025 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5675: rename

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene5675@1595026 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5675: break out IntersectTermsEnumFrame

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene5675@1595027 13f79535-47bb-0310-9956-ffa450edef68