Revert "skia: Add workaround header define"

This reverts commit b3fdac1b.

Reason for revert: no longer needed
Causes breakages in https://chromium-review.googlesource.com/c/chromium/src/+/1018402
Will roll Skia patch first and then reland this.

Original change's description:
> skia: Add workaround header define
> 
> Chromium-side changes for:
> https://skia-review.googlesource.com/c/skia/+/120608
> 
> Bug: 829614
> Change-Id: I59dc05ae1d66622ce3c771311ec3e1b64023b66f
> Reviewed-on: https://chromium-review.googlesource.com/1008924
> Reviewed-by: Brian Salomon <bsalomon@chromium.org>
> Commit-Queue: enne <enne@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#551370}

TBR=bsalomon@chromium.org,enne@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 829614
Change-Id: I7512e16d2023c51407c2d3bc8b2969dc067d5f91
Reviewed-on: https://chromium-review.googlesource.com/1019730Reviewed-by: enne <enne@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552223}

skia/BUILD.gn

@@ -68,9 +68,6 @@ config("skia_config") {
     ]
   }
 
-  workaround_header = "gpu/config/gpu_driver_bug_workaround_autogen.h"
-  defines += [ "SK_GPU_WORKAROUNDS_HEADER=\"$workaround_header\"" ]
-
   if (is_component_build) {
     defines += [
       "SKIA_DLL",