HIVE-8278: Restoring a graph representation of SparkPlan [Spark Branch] (Chao via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1628450 13f79535-47bb-0310-9956-ffa450edef68
HIVE-8302: GroupByShuffler.java missing apache license header [Spark Branch] (Chao via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1628452 13f79535-47bb-0310-9956-ffa450edef68