cmd/go: Skip note reading test with linkmode external on openbsd/arm

openbsd/arm does not support external linking - skip the note reading test that
uses linkmode external on this platform. While here, cleanup the code and
consistently use t.Skipf for all platforms that cannot run this test.

Change-Id: I64f0d9e038bc4c993c3d843fc069a0b723a924d6
Reviewed-on: https://go-review.googlesource.com/15054Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/go/note_test.go

@@ -24,27 +24,23 @@ func TestNoteReading(t *testing.T) {
 		t.Fatalf("buildID in hello binary = %q, want %q", id, buildID)
 	}
 
-	if runtime.GOOS == "linux" && (runtime.GOARCH == "ppc64le" || runtime.GOARCH == "ppc64") {
-		t.Skipf("skipping - golang.org/issue/11184")
-	}
-
-	if runtime.GOOS == "linux" && (runtime.GOARCH == "mips64le" || runtime.GOARCH == "mips64") {
+	switch {
+	case runtime.GOOS == "linux" && (runtime.GOARCH == "ppc64le" || runtime.GOARCH == "ppc64"):
+		t.Skipf("skipping - external linking not supported, golang.org/issue/11184")
+	case runtime.GOOS == "linux" && (runtime.GOARCH == "mips64le" || runtime.GOARCH == "mips64"):
 		t.Skipf("skipping - external linking not supported, golang.org/issue/12560")
+	case runtime.GOOS == "openbsd" && runtime.GOARCH == "arm":
+		t.Skipf("skipping - external linking not supported, golang.org/issue/10619")
+	case runtime.GOOS == "plan9":
+		t.Skipf("skipping - external linking not supported")
 	}
 
-	switch runtime.GOOS {
-	case "plan9":
-		// no external linking
-		t.Logf("no external linking - skipping linkmode=external test")
-
-	default:
-		tg.run("build", "-ldflags", "-buildid="+buildID+" -linkmode=external", "-o", tg.path("hello.exe"), tg.path("hello.go"))
-		id, err := main.ReadBuildIDFromBinary(tg.path("hello.exe"))
-		if err != nil {
-			t.Fatalf("reading build ID from hello binary (linkmode=external): %v", err)
-		}
-		if id != buildID {
-			t.Fatalf("buildID in hello binary = %q, want %q (linkmode=external)", id, buildID)
-		}
+	tg.run("build", "-ldflags", "-buildid="+buildID+" -linkmode=external", "-o", tg.path("hello.exe"), tg.path("hello.go"))
+	id, err = main.ReadBuildIDFromBinary(tg.path("hello.exe"))
+	if err != nil {
+		t.Fatalf("reading build ID from hello binary (linkmode=external): %v", err)
+	}
+	if id != buildID {
+		t.Fatalf("buildID in hello binary = %q, want %q (linkmode=external)", id, buildID)
 	}
 }