cmd/internal/obj/arm: handle HAUTO etc. in addpool

cmd/internal/obj/arm: handle HAUTO etc. in addpool

HAUTO should be handled the same way as other stack offsets for
adding to constant pool. Add the missing cases.

Fixes #57955.

Change-Id: If7fc82cafb2bbf0a6121e73e353b8825cb36b5bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/463138
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>