runtime/internal/atomic: fix s390x's StorepNoWB implementation
runtime/internal/atomic: fix s390x's StorepNoWB implementation

Same as CL 170323, but for s390x instead of wasm.

Fixes #31495.

Change-Id: Ie39f649f5e33690375a8bcb1bc3b92d912ca4398
Reviewed-on: https://go-review.googlesource.com/c/go/+/172417
Run-TryBot: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@google.com>
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

akutz/go,akutz/go,akutz/go,golang/go,nawawi/go,cloudflare/go,nawawi/go,nawawi/go,golang/go,CAFxX/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,josharian/go,josharian/go,akutz/go,josharian/go,CAFxX/go,nawawi/go,cloudflare/go,cloudflare/go,cloudflare/go,akutz/go,golang/go,nawawi/go,josharian/go,akutz/go,golang/go,golang/go,cloudflare/go,golang/go,CAFxX/go,josharian/go,CAFxX/go,CAFxX/go,CAFxX/go,josharian/go,CAFxX/go,golang/go,akutz/go,cloudflare/go,cloudflare/go,akutz/go,golang/go,josharian/go,nawawi/go,josharian/go