Implement import scope

tests/language/library4_negative_test.dart

Index: tests/language/library4_negative_test.dart
===================================================================
--- tests/language/library4_negative_test.dart	(revision 10922)
+++ tests/language/library4_negative_test.dart	(working copy)
@@ -1,14 +0,0 @@
-// 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.
-
-// This test should fail to load because library1 defines a top-level
-// variable named 'foo' which conflicts with the prefix 'foo' used to import
-// library3.  This is an error even if 'foo' is never referred to.
-
-#library("Library4NegativeTest.dart");
-#import("library1.dart"); // Defines a top-level variable 'foo'
-#import("library3.dart", prefix:"foo"); // Creates prefix 'foo'
-
-main() {
-}