Fix color emoji.

Removes the GrMaskFormat and single atlas in GrTextStrike.
Replaces it by storing the GrMaskFormat in each GrGlyph, and
doing a lookup for the correct atlas based on that.

Disables color glyph rendering in GrDistanceFieldTextContext
for now.

BUG=skia:2887

Review URL: https://codereview.chromium.org/636183005
Revert of Fix color emoji. (patchset #11 id:320001 of https://codereview.chromium.org/636183005/)

Reason for revert:
Crashing the Windows bots.

Original issue's description:
> Fix color emoji.
>
> Removes the GrMaskFormat and single atlas in GrTextStrike.
> Replaces it by storing the GrMaskFormat in each GrGlyph, and
> doing a lookup for the correct atlas based on that.
>
> Disables color glyph rendering in GrDistanceFieldTextContext
> for now.
>
> BUG=skia:2887
>
> Committed: https://skia.googlesource.com/skia/+/bc92163ddfe957ad6ffbb02ac40e0ba75ff82216

TBR=robertphillips@google.com,bungeman@google.com,reed@google.com,bsalomon@google.com
NOTREECHECKS=true
NOTRY=true
BUG=skia:2887

Review URL: https://codereview.chromium.org/640413004
detect --loops is < 0 and interpret that as running forever (mostly)

BUG=skia:

Review URL: https://codereview.chromium.org/643143002
Opt state takes a GP instead of a GeometryStage

BUG=skia:

Review URL: https://codereview.chromium.org/637003003