runtime: skip test on darwin/arm

Needs the Go tool, which we do not have on iOS. (No Fork.)

Change-Id: Iedf69f5ca81d66515647746546c9b304c8ec10c4
Reviewed-on: https://go-review.googlesource.com/6102Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

src/runtime/runtime_test.go

@@ -98,6 +98,10 @@ func TestRuntimeGogoBytes(t *testing.T) {
 	switch GOOS {
 	case "android", "nacl":
 		t.Skipf("skipping on %s", GOOS)
+	case "darwin":
+		if GOARCH == "arm" {
+			t.Skipf("skipping on %s/%s", GOOS, GOARCH)
+		}
 	}
 
 	dir, err := ioutil.TempDir("", "go-build")
@@ -261,8 +265,8 @@ func TestTrailingZero(t *testing.T) {
 		n int64
 		z struct{}
 	}
-	if unsafe.Sizeof(T2{}) != 8 + unsafe.Sizeof(Uintreg(0)) {
-		t.Errorf("sizeof(%#v)==%d, want %d", T2{}, unsafe.Sizeof(T2{}), 8 + unsafe.Sizeof(Uintreg(0)))
+	if unsafe.Sizeof(T2{}) != 8+unsafe.Sizeof(Uintreg(0)) {
+		t.Errorf("sizeof(%#v)==%d, want %d", T2{}, unsafe.Sizeof(T2{}), 8+unsafe.Sizeof(Uintreg(0)))
 	}
 	type T3 struct {
 		n byte