cmd/objdump: skip test on android (no Go tool)

LGTM=minux, iant
R=golang-codereviews, minux, iant
CC=golang-codereviews
https://golang.org/cl/109570043

src/cmd/objdump/objdump_test.go

@@ -19,8 +19,9 @@ import (
 )
 
 func loadSyms(t *testing.T) map[string]string {
-	if runtime.GOOS == "nacl" {
-		t.Skip("skipping on nacl")
+	switch runtime.GOOS {
+	case "android", "nacl":
+		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
 	cmd := exec.Command("go", "tool", "nm", os.Args[0])
@@ -44,8 +45,9 @@ func loadSyms(t *testing.T) map[string]string {
 }
 
 func runObjDump(t *testing.T, exe, startaddr, endaddr string) (path, lineno string) {
-	if runtime.GOOS == "nacl" {
-		t.Skip("skipping on nacl")
+	switch runtime.GOOS {
+	case "android", "nacl":
+		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
 	cmd := exec.Command(exe, os.Args[0], startaddr, endaddr)
@@ -111,8 +113,9 @@ func TestObjDump(t *testing.T) {
 }
 
 func buildObjdump(t *testing.T) (tmp, exe string) {
-	if runtime.GOOS == "nacl" {
-		t.Skip("skipping on nacl")
+	switch runtime.GOOS {
+	case "android", "nacl":
+		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
 	tmp, err := ioutil.TempDir("", "TestObjDump")