move more geometry to simd

Remove duplicate quad and cubic code around
computing the polynomial coefficients, and
use common SIMD-based code instead.

R=reed@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1633143002

Review URL: https://codereview.chromium.org/1633143002
4 files changed