dart2js: remove (broken) support for nsm on native classes.

pkg/compiler/lib/src/warnings.dart

Index: pkg/compiler/lib/src/warnings.dart
diff --git a/pkg/compiler/lib/src/warnings.dart b/pkg/compiler/lib/src/warnings.dart
index 75334eabab3a260b369453f4a72697adbc2e8ebd..6a78b8adff1a26d5283a59e0f4e2252c52ed21cf 100644
--- a/pkg/compiler/lib/src/warnings.dart
+++ b/pkg/compiler/lib/src/warnings.dart
@@ -1271,6 +1271,11 @@ main() => A.A = 1;
   static const MessageKind MISSING_FACTORY_KEYWORD = const MessageKind(
       "Did you forget a factory keyword here?");
 
+  static const MessageKind NO_SUCH_METHOD_IN_NATIVE =
+      const MessageKind(
+          "'NoSuchMethod' is not supported for classes that extend native "
+          "classes.");
+
   static const MessageKind DEFERRED_LIBRARY_DART_2_DART =
       const MessageKind(
           "Deferred loading is not supported by the dart backend yet."