[dev.simd] cmd/compile: don't require single use for SIMD load/store folding
For load and store on scalar values, we fold the address to the
load/stoer instruction without requiring the address having one
use. Do the same for SIMD, and remove the single use check.
Change-Id: Ie7d1bbae1b32bb8c069548197632edae36b419b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/707137 Reviewed-by: Junyang Shao <shaojunyang@google.com> Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>