XSAVE, XSAVEOPT, XSAVEC and XSAVES with their restore twins, plain and
64, each pinned byte for byte against go tool asm through every corpus
line the toolchain's own amd64enc.s carries for the family (24 lines).
The toolchain emits XSAVEOPT without the manual's 0x66 prefix; the bytes
are the oracle, so the family carries none.
Assisted-by: GLM 5.3 Flash
