GPU Calc: fix a parallel COUNT() problem when input vector size > 512

AMLOEXT-243 FIX

Change-Id: I1a356f9a591c1f5a99d2675065b63a7673217ac6
GPU Calc: test case for parallel count()

AMLOEXT-243 BUG

Change-Id: I97e2dab35b40f4f7fcd4975ae7c5907e97e19fd9