Improve the performance of Hive on Spark 2.0.0

In HIVE-14029, we have updated Spark dependency to 2.0.0. We use Intel BigBench[1] to run benchmark with Spark 2.0 over 1 TB data set comparing with Spark 1.6. We can see performance improvments about 5.4% in general and 45% for the best case. However, some queries doesn't have significant performance improvements. This JIRA is the umbrella ticket addressing those performance issues.

[1] https://github.com/intel-hadoop/Big-Data-Benchmark-for-Big-Bench