Revert of Work around for nexus 6 TexSubImage issue (patchset #4 id:60001 of https...

Revert of Work around for nexus 6 TexSubImage issue (patchset #4 id:60001 of https://codereview.chromium.org/1173203005/)

Reason for revert:
breaks gms

Original issue's description:
> Work around for nexus 6 TexSubImage issue
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/c69fe20ef35df0776b179cbd5ce4d1bdc0ba4090

TBR=bsalomon@google.com,joshualitt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1190463006