[dev.simd] internal/cpu: add AVX-512-CD and DQ, and derived "basic AVX-512"
This adds detection for the CD and DQ sub-features of x86 AVX-512.
Building on these, we also add a "derived" AVX-512 feature that
bundles together the basic usable subset of subfeatures. Despite the F
in AVX-512-F standing for "foundation", AVX-512-F+BW+DQ+VL together
really form the basic usable subset of AVX-512 functionality. These
have also all been supported together by almost every CPU, and are
guaranteed by GOAMD64=v4, so there's little point in separating them
out.
Change-Id: I34356502bd1853ba2372e48db0b10d55cffe07a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/680899 Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>