HIVE-4124

Summary: Tests for windowing.

Test Plan: The patch only contains tests.

Reviewers: hbutani

Differential Revision: https://reviews.facebook.net/D9099

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/ptf-windowing@1453035 13f79535-47bb-0310-9956-ffa450edef68