Remove support for the DeferredLibrary annotation and remove tests of it

tests/language/deferred_no_such_method_test.dart

Index: tests/language/deferred_no_such_method_test.dart
diff --git a/tests/language/deferred_no_such_method_test.dart b/tests/language/deferred_no_such_method_test.dart
index 00791b5facd9b300fd6d4997d960123ebe043784..9f1b232ce6d9dc4b483c9d6ff71c60f809239bee 100644
--- a/tests/language/deferred_no_such_method_test.dart
+++ b/tests/language/deferred_no_such_method_test.dart
@@ -2,17 +2,14 @@
 // 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.
 
-import "dart:async";
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
 
-@l import "deferred_no_such_method_lib.dart" as lib;
-
-const l = const DeferredLibrary('lib');
+import "deferred_no_such_method_lib.dart" deferred as lib;
 
 void main() {
   asyncStart();
-  l.load().then((_) {
+  lib.loadLibrary().then((_) {
     Expect.equals(42, new lib.C().nonExisting());
     asyncEnd();
   });