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>
diff --git a/tools/skpbench/skpbench.py b/tools/skpbench/skpbench.py
index 1db66af..a9ec618 100755
--- a/tools/skpbench/skpbench.py
+++ b/tools/skpbench/skpbench.py
@@ -75,10 +75,6 @@
   type=int, default=0, help="number of tiles along one edge when in DDL mode")
 __argparse.add_argument('--ddlRecordTime',
   action='store_true', help="report just the cpu time spent recording DDLs")
-__argparse.add_argument('--gpuThreads',
-  type=int, default=2,
-  help="Create this many extra threads to assist with GPU work, including"
-       " software path rendering. Defaults to two.")
 __argparse.add_argument('skps',
   nargs='+',
   help=".skp files or directories to expand for .skp files")
@@ -133,8 +129,6 @@
     ARGV.extend(['--pr'] + re.split(r'[ ,]', FLAGS.pr))
   if FLAGS.nocache:
     ARGV.extend(['--cachePathMasks', 'false'])
-  if FLAGS.gpuThreads:
-    ARGV.extent(['--gpuThreads', str(FLAGS.gpuThreads)])
 
   # DDL parameters
   if FLAGS.ddl: