PIG-4104: Accumulator UDF throws OOM in Tez (rohini)

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1625091 13f79535-47bb-0310-9956-ffa450edef68
PIG-4169: NPE in ConstantCalculator

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1625205 13f79535-47bb-0310-9956-ffa450edef68
PIG-4170: Multiquery with different type of key gives wrong result

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1625216 13f79535-47bb-0310-9956-ffa450edef68