[dev.ssa] cmd/compile/internal/gc: fix tests on non-amd64

Change-Id: Ibd6a59db2d5feea41a21fbea5c1a7fdd49238aa8
Reviewed-on: https://go-review.googlesource.com/12131Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/ssa_test.go

@@ -8,11 +8,18 @@ import (
 	"bytes"
 	"internal/testenv"
 	"os/exec"
+	"runtime"
 	"strings"
 	"testing"
 )
 
+// Tests OANDAND and OOROR expressions and short circuiting.
+// TODO: move these tests elsewhere? perhaps teach test/run.go how to run them
+// with a new action verb.
 func TestShortCircuit(t *testing.T) {
+	if runtime.GOARCH != "amd64" {
+		t.Skipf("skipping SSA tests on %s for now", runtime.GOARCH)
+	}
 	testenv.MustHaveGoBuild(t)
 	var stdout, stderr bytes.Buffer
 	cmd := exec.Command("go", "run", "testdata/short_ssa.go")