Revert of Make NVPR a GL context option instead of a GL context (patchset #2 id:20001 of https://codereview.chromium.org/1448883002/ )

Reason for revert:
BUG=skia:4609

skbug.com/4609

Seems like GrContextFactory needs to fail when the NVPR option is requested but the driver version isn't sufficiently high.

Original issue's description:
> Make NVPR a GL context option instead of a GL context
>
> Make NVPR a GL context option instead of a GL context.
> This may enable NVPR to be run with command buffer
> interface.
>
> No functionality change in DM or nanobench. NVPR can
> only be run with normal GL APIs.
>
> BUG=skia:2992
>
> Committed: https://skia.googlesource.com/skia/+/eeebdb538d476c1bfc8b63a946094ca1b505ecd1

TBR=mtklein@google.com,jvanverth@google.com,kkinnunen@nvidia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:2992

Review URL: https://codereview.chromium.org/1486153002
11 files changed