Graduate matrix map-point procs out of SkOpts.

Graduate matrix map-point procs out of SkOpts.

These are implemented generically with Sk4s and don't benefit
from anything fancier than vanilla SSE/NEON.

This means there's no need to hide this code away in another
file or behind a function pointer... it's readable and we have
compile-time support for all the instructions it needs.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1872193002
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot

Review URL: https://codereview.chromium.org/1872193002