PIG-3846: Implement automatic reducer parallelism

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1603243 13f79535-47bb-0310-9956-ffa450edef68
PIG-3983: TestGrunt.testKeepGoigFailed fail on tez mode

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1603245 13f79535-47bb-0310-9956-ffa450edef68
PIG-4013: Order by multiple column fail on Tez

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1603246 13f79535-47bb-0310-9956-ffa450edef68
PIG-4014: Fix Rank e2e test failures on tez

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1603248 13f79535-47bb-0310-9956-ffa450edef68
PIG-4017: NPE thrown from JobControlCompiler.shipToHdfs (cheolsoo)


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