HIVE-5271: Convert join op to a map join op in the planning phase (Vikram Dixit K via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/tez@1527686 13f79535-47bb-0310-9956-ffa450edef68
HIVE-5368: Changes to work creation for tez (Vikram Dixit K via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/tez@1527689 13f79535-47bb-0310-9956-ffa450edef68