PIG-3761: Outer join fail on tez

git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1570026 13f79535-47bb-0310-9956-ffa450edef68
PIG-3769: Scripting UDF is broken after PIG-3629

git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1570028 13f79535-47bb-0310-9956-ffa450edef68