GPU Calc: separate out parallel reduction from DynamicKernelSlidingArgument
GPU Calc: separate out parallel reduction from DynamicKernelSlidingArgument

Create a new class ParallelReductionVectorRef to straighten out code
generation and marshaling logic between sequential and parallel code
generation alternatives.

Change-Id: Id029ad441f80712f8e7396dcd985e3363ce08ff8

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core