HIVE-8536: Enable SkewJoinResolver for spark [Spark Branch] (Rui via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1643744 13f79535-47bb-0310-9956-ffa450edef68
HIVE-9019 - Avoid using SPARK_JAVA_OPTS [Spark Branch] (Rui Li via Brock)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1643896 13f79535-47bb-0310-9956-ffa450edef68
HIVE-9040 - Spark Memory can be formatted string [Spark Branch] (Jimmy Xiang via Brock)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1643962 13f79535-47bb-0310-9956-ffa450edef68
HIVE-8638: Implement bucket map join optimization [Spark Branch] (Jimmy via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1643976 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'upstream/spark' into spark