runtime/testdata: fix testprogcgo for windows/arm64

Our toolchain does not like -mnop-fun-dllimport.

Change-Id: Iaaee01fe0f4b0959406a35eb13aefa390116b483
Reviewed-on: https://go-review.googlesource.com/c/go/+/312043


Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>