Reland "Use conics with w=Inf to describe triangles for the tessellator"

This is a reland of 84f70136abfb0af3cddf2ec7e8e2405f154916b0

Original change's description:
> Use conics with w=Inf to describe triangles for the tessellator
>
> Previously, only the indirect tessellator could draw triangles, and
> only with special index data. Using conics with w=Inf will allow us to
> draw triangles with the hardware tessellator as well, in addition to
> being able to wean the indirect tessellator off an index buffer.
>
> Bug: skia:10419
> Bug: chromium:1202607
> Change-Id: I180af9cb5410c0e0bb25a2edcfb01e17d4a2f590
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/406977
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>

Bug: skia:10419
Bug: chromium:1202607
Change-Id: Ic12b10eaa60fddd212c66757bf7100749ee58d49
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/408096
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
5 files changed