This visitor visits the MRPlan and does the following
for each MROper
- visits the POPackage in the reduce plan and finds the corresponding
POLocalRearrange(s) (either in the map plan of the same oper OR
reduce plan of predecessor MROper). It then annotates the POPackage
with information about which columns in the "value" are present in the
"key" and will need to stitched in to the "value"
Fields inherited from class org.apache.pig.impl.plan.PlanVisitor