PIG-4146: Create a target to run mr and tez unit test in one shot

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1622378 13f79535-47bb-0310-9956-ffa450edef68
PIG-4149: Rounding issue in FindQuantiles

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1622379 13f79535-47bb-0310-9956-ffa450edef68
PIG-4143: Port more mini cluster tests to Tez - part 7

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1622382 13f79535-47bb-0310-9956-ffa450edef68
PIG-4143: Port more mini cluster tests to Tez - part 7

git-svn-id: https://svn.apache.org/repos/asf/pig/trunk@1622383 13f79535-47bb-0310-9956-ffa450edef68