Revert of Explicit control in tools of ANGLE frontend and backend (patchset #6 id...

Revert of Explicit control in tools of ANGLE frontend and backend (patchset #6 id:90001 of https://codereview.chromium.org/2381033002/ )

Reason for revert:
Broke bots

Original issue's description:
> Explicit control in tools of ANGLE frontend and backend
>
> Update the ANGLE test GL context, GrContextFactory, and config parsing to allow explicit control of ANGLE front/backend.
>
> This will allow us to explicitly test ES2 vs ES3 interfaces to ANGLE as well as D3D9, D3D11, and OpenGL backends.
>
> Also makes the angle api types valid in all builds (but will just fail when SK_ANGLE=1 or not on windows for the d3d backends).
>
> BUG=skia:5804
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2381033002
>
> Committed: https://skia.googlesource.com/skia/+/50094fb489543655df026be4e4f99e09e57a1f49

TBR=brianosman@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:5804

Review-Url: https://codereview.chromium.org/2384483003