HIVE-7283: CBO: plumb in HepPlanner and FieldTrimmer(ColumnPruner) into Optiq based planning (Harish Butani via Gunther Hagleitner)

git-svn-id: https://svn.apache.org/repos/asf/hive/branches/cbo@1606302 13f79535-47bb-0310-9956-ffa450edef68