HIVE-8793: Refactor to make splitting SparkWork a physical resolver [Spark Branch] (Rui via Xuefu)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/spark@1638907 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'upstream/spark' into spark