[dev.simd] cmd/compile, simd: update generated files

This CL is generated by x/arch CL 694859.

Change-Id: I18bd076e26e93bc2fb0e761de26511138e95055f
Reviewed-on: https://go-review.googlesource.com/c/go/+/694916
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>

Author: aclements