Revert "Quad intersections for glyph underlines"

This reverts commit 46d65bbd51bb1e0302bc5bbadbc2d956dd9350b5.

Reason for revert: Assert when quad is linear

Original change's description:
> Quad intersections for glyph underlines
>
> Introduce Intersect that takes two quadratics, and a
> toIntersect value. It finds the roots that intersect
> toIntersect in the first quadratic, and then uses those
> roots to generate values from the second quadratic.
>
> Use Intersect to implement underline for glyphs with
> quadratic curves.
>
> Bug: skia:14252
> Change-Id: I48c4f3edf687c0bfef3a6110251e3e34062d3b39
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/708379
> Reviewed-by: Herb Derby <herb@google.com>
> Commit-Queue: Herb Derby <herb@google.com>
> Reviewed-by: Kevin Lubick <kjlubick@google.com>

Bug: skia:14252
Change-Id: I9a83a1c8d2be8b51e2902724cf8061e7ee21dda8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/711656
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Herb Derby <herb@google.com>
5 files changed