exp/types: disable test

It's broken and seems to be exp/types's fault.

Update #3682.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6243068

src/pkg/exp/types/gcimporter_test.go

@@ -92,6 +92,13 @@ func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
 }
 
 func TestGcImport(t *testing.T) {
+	// Dies trying to read crypto/md5, which contains
+	//	const init1 = 0x...
+	// The importer believes init1 should be a function for some reason.
+	// golang.org/issue/3682.
+	t.Logf("broken; skipping")
+	return
+
 	// On cross-compile builds, the path will not exist.
 	// Need to use GOHOSTOS, which is not available.
 	if _, err := os.Stat(gcPath); err != nil {