Revert "Add --gpuThreads support to skpbench.py"

This reverts commit 2f14f21acbd291933e13e8eef822fd222d20c677.

Reason for revert: python

Original change's description:
> Add --gpuThreads support to skpbench.py
> 
> Change-Id: Ib5c7ed0fd28ebf734168bc0377d643bbddf70e65
> Reviewed-on: https://skia-review.googlesource.com/134601
> Reviewed-by: Greg Daniel <egdaniel@google.com>
> Commit-Queue: Robert Phillips <robertphillips@google.com>

TBR=egdaniel@google.com,robertphillips@google.com

Change-Id: I428a8b6d7cf945c8609a36cf5c912d6ebc517201
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/134640
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
1 file changed