HIVE-9116: Add unit test for multi sessions.[Spark Branch] (Chengxiang via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1646504 13f79535-47bb-0310-9956-ffa450edef68
HIVE-9136: Profile query compiler [Spark Branch] (Chao via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1646506 13f79535-47bb-0310-9956-ffa450edef68
HIVE-9094: TimeoutException when trying get executor count from RSC [Spark Branch] (Chengxiang via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1646511 13f79535-47bb-0310-9956-ffa450edef68
HIVE-9127: Improve CombineHiveInputFormat.getSplit performance (Brock via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1646512 13f79535-47bb-0310-9956-ffa450edef68
HIVE-8639: Convert SMBJoin to MapJoin [Spark Branch] (Szehon via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1646523 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'upstream/spark' into spark