cmd/compile: (loong64) optimize float32(abs|sqrt64(float64(x)))

cmd/compile: (loong64) optimize float32(abs|sqrt64(float64(x)))

Ref: #733621
Updates #75463

Change-Id: Idd8821d1713754097a2fe83a050c25d9ec5b17eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/735540
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>