Make pub strong-mode clean.

test/pub_uploader_test.dart

Index: test/pub_uploader_test.dart
diff --git a/test/pub_uploader_test.dart b/test/pub_uploader_test.dart
index 4eb85ee970e951163ebb0e178b3305a9a687fb14..3f4c1b3857d5aa401722b5b5b6b055bae84ae500 100644
--- a/test/pub_uploader_test.dart
+++ b/test/pub_uploader_test.dart
@@ -32,7 +32,7 @@ See http://dartlang.org/tools/pub/cmd/pub-uploader.html for detailed documentati
 ScheduledProcess startPubUploader(ScheduledServer server, List<String> args) {
   var tokenEndpoint = server.url.then((url) =>
       url.resolve('/token').toString());
-  args = flatten(['uploader', '--server', tokenEndpoint, args]);
+  args = ['uploader', '--server', tokenEndpoint]..addAll(args);
   return startPub(args: args, tokenEndpoint: tokenEndpoint);
 }