cmd/callgraph: expand windows/arm64 skip to the whole platform

This test produces apparent file corruption on all of the
windows/arm64 builders. I suspect that this is a low-level bug (in
either the platform itself or the Go standard library on
windows/arm64).

Since windows/arm64 is not yet a first-class port, this test can be
skipped for now. However, if windows/arm64 becomes a first-class port
the underlying file-corruption bug should be investigated and fixed.

Updates golang/go#50706.

Change-Id: I0bc80cefee50895d40acc658286eb7ef8790493a
Reviewed-on: https://go-review.googlesource.com/c/tools/+/397996
Reviewed-by: Russ Cox <rsc@golang.org>
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

cmd/callgraph/main_test.go

@@ -15,6 +15,7 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -34,8 +35,8 @@ func init() {
 }
 
 func TestCallgraph(t *testing.T) {
-	if b := os.Getenv("GO_BUILDER_NAME"); b == "windows-arm64-10" {
-		t.Skipf("skipping due to suspected file corruption bug on %s builder (https://go.dev/issue/50706)", b)
+	if runtime.GOOS == "windows" && runtime.GOARCH == "arm64" {
+		t.Skipf("skipping due to suspected file corruption bug on windows/arm64 (https://go.dev/issue/50706)")
 	}
 
 	testenv.NeedsTool(t, "go")