PIG-3742: Set MR runtime settings on tez runtime

git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1565502 13f79535-47bb-0310-9956-ffa450edef68
PIG-3748: Support for multiquery off in Tez

git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1565509 13f79535-47bb-0310-9956-ffa450edef68
Tiny fix to make Pig compile

git-svn-id: https://svn.apache.org/repos/asf/pig/branches/tez@1565513 13f79535-47bb-0310-9956-ffa450edef68