Add an option to run skipped tests.

lib/src/backend/declarer.dart

Index: lib/src/backend/declarer.dart
diff --git a/lib/src/backend/declarer.dart b/lib/src/backend/declarer.dart
index 6aef7af3839bceeac2fe289e5feea39d5cc82b83..216865b9f1740f917300db7b4c5a3e02e594058a 100644
--- a/lib/src/backend/declarer.dart
+++ b/lib/src/backend/declarer.dart
@@ -119,12 +119,6 @@ class Declarer {
         tags: tags));
     var trace = new Trace.current(2);
 
-    // Don't load the tests for a skipped group.
-    if (metadata.skip) {
-      _entries.add(new Group(name, [], metadata: metadata, trace: trace));
-      return;
-    }
-
     var declarer = new Declarer._(this, _prefix(name), metadata, trace);
     declarer.declare(body);
     _entries.add(declarer.build());