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

LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews
https://golang.org/cl/107600043

src/cmd/pack/pack_test.go

@@ -186,8 +186,9 @@ func TestExtract(t *testing.T) {
 
 // Test that pack-created archives can be understood by the tools.
 func TestHello(t *testing.T) {
-	if runtime.GOOS == "nacl" {
-		t.Skip("skipping on nacl")
+	switch runtime.GOOS {
+	case "android", "nacl":
+		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
 	dir := tmpDir(t)
@@ -222,8 +223,9 @@ func TestHello(t *testing.T) {
 
 // Test that pack works with very long lines in PKGDEF.
 func TestLargeDefs(t *testing.T) {
-	if runtime.GOOS == "nacl" {
-		t.Skip("skipping on nacl")
+	switch runtime.GOOS {
+	case "android", "nacl":
+		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
 	dir := tmpDir(t)