HIVE-8225 : CBO trunk merge: union11 test fails due to incorrect plan (Pengcheng Xiong, reviewed by Sergey Shelukhin, Laljo John Pullokkaran)

git-svn-id: https://svn.apache.org/repos/asf/hive/trunk@1631578 13f79535-47bb-0310-9956-ffa450edef68