Revert of Added a GLBench for testing performance of vec4 vs scalar for coverage in generated shaders. (patchset #6 id:90001 of https://codereview.chromium.org/1225383002/)

Reason for revert:
Still failing on Windows. e.g. https://uberchromegw.corp.google.com/i/client.skia/builders/Perf-Win8-MSVC-ShuttleB-GPU-HD4600-x86_64-Release-ANGLE/builds/231/steps/nanobench/logs/stdio

skbug.com/4053

Original issue's description:
> Added a glBench for testing performance of vec4 vs scalar coverage in generated shaders.
>
> Added bench for timing vec4 vs scalar type for coverage in shaders
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/6104ced165f17eb2f765ace354d5895c0bc890c5
>
> Committed: https://skia.googlesource.com/skia/+/c734e69e8cf94bacaf68d3d8ee3310d1ad1fe8b8

TBR=joshualitt@google.com,tomhudson@google.com,wangyix@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1239503003
1 file changed