IMPALA-1249: Anti joins have a uni-directional value transfer.

Like left/right outer joins, anti joins have a uni-directional value transfer.
Predicates could be pushed into anti joined plan subtrees if the condition
was inverted, but this patch does not implement this optimization.

No special consideration must be made to prevent predicate assignment
into anti-joined branches because anti-joined tuples are invisible outside
of the On-clause, and therefore, all unassigned conjuncts referencing the
invisible tuple must come from the original join's On-clause. The assignment
of such predicates is already handled correctly.

Change-Id: Ic2b94f6eb57e000ea51e253035e713288b205298
Reviewed-on: http://gerrit.sjc.cloudera.com:8080/4425
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: jenkins