Rollback PIG-3979: group all performance, garbage collection, and incremental aggregation

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1632669 13f79535-47bb-0310-9956-ffa450edef68
PIG-4184: UDF backward compatibility issue after POStatus.STATUS_NULL refactory

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1632673 13f79535-47bb-0310-9956-ffa450edef68