fix Library*NegativeTests (and a couple Prefix ones by accident)

frog/world.dart

Index: frog/world.dart
diff --git a/frog/world.dart b/frog/world.dart
index d1e098ad9b79bcec468e97df6e147da056a267ee..16d1b2db68c012ed724fc500fe65da3a75ba685d 100644
--- a/frog/world.dart
+++ b/frog/world.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -430,6 +430,9 @@ class World {
     for (var lib in libraries.getValues()) {
       lib.resolve();
     }
+    for (var lib in libraries.getValues()) {
+      lib.postResolveChecks();
+    }
   }
 
   findMainMethod(Library lib) {