net: clean the dregs of NaCL merge

LGTM=iant, aram, dave
R=golang-codereviews, iant, aram, dave
CC=golang-codereviews
https://golang.org/cl/68770044
diff --git a/src/pkg/net/file_test.go b/src/pkg/net/file_test.go
index 09d1f4d..d81bca7 100644
--- a/src/pkg/net/file_test.go
+++ b/src/pkg/net/file_test.go
@@ -181,7 +181,7 @@
 
 func TestFilePacketConn(t *testing.T) {
 	switch runtime.GOOS {
-	case "plan9", "windows", "nacl":
+	case "nacl", "plan9", "windows":
 		t.Skipf("skipping test on %q", runtime.GOOS)
 	}