HIVE-7283 CBO: plumb in HepPlanner and FieldTrimmer(ColumnPruner) into Optiq based planning (harish Butani reviewed by John P)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1605453 13f79535-47bb-0310-9956-ffa450edef68