Support @Skip as a suite-level annotation.

lib/src/runner/loader.dart

Index: lib/src/runner/loader.dart
diff --git a/lib/src/runner/loader.dart b/lib/src/runner/loader.dart
index 7652165d1eaaaf90c8ecc144f71ed6435928a7e1..1b4aafa83bff29693e9556632b3b75b266e7589c 100644
--- a/lib/src/runner/loader.dart
+++ b/lib/src/runner/loader.dart
@@ -127,14 +127,15 @@ class Loader {
     var controller = new StreamController();
     Future.forEach(_platforms, (platform) {
       if (!metadata.testOn.evaluate(platform, os: currentOS)) {
-        return new Future.value();
+        return;
       }
 
       // Don't load a skipped suite.
       if (metadata.skip) {
-        return new Future.value(new Suite([
+        controller.add(new Suite([
           new LocalTest(path, metadata, () {})
         ], path: path, platform: platform.name, metadata: metadata));
+        return;
       }
 
       return new Future.sync(() {