Handle platform access through prefix in dart2dart

tests/language/regress_21998_lib2.dart

Index: tests/language/regress_21998_lib2.dart
diff --git a/tests/compiler/dart2js/http_launch_data/http_launch_main.dart b/tests/language/regress_21998_lib2.dart
similarity index 52%
copy from tests/compiler/dart2js/http_launch_data/http_launch_main.dart
copy to tests/language/regress_21998_lib2.dart
index 68ea63472f29d5b7d7d4de8a863c4d05cd7db0bd..8d1ac8934162980fe9353119e7b035bc27e59a09 100644
--- a/tests/compiler/dart2js/http_launch_data/http_launch_main.dart
+++ b/tests/language/regress_21998_lib2.dart
@@ -1,10 +1,9 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2015, 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.
 
+library regress_21998_lib2;
 
-import 'lib1.dart';
+import 'dart:math';
 
-main() {
-  print(foo());
-}
+lib2_max(a, b) => max(a, b);