Test that built-in identifiers can be used as library prefixes.

dart/tests/language/built_in_identifier_prefix_library_external.dart

Index: dart/tests/language/built_in_identifier_prefix_library_external.dart
diff --git a/dart/tests/language/built_in_identifier_prefix_library_external.dart b/dart/tests/language/built_in_identifier_prefix_library_external.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f4b90cb505a10d1eb7668a8958e48a5600c5bb59
--- /dev/null
+++ b/dart/tests/language/built_in_identifier_prefix_library_external.dart
@@ -0,0 +1,14 @@
+// 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.
+
+library external;
+
+class A {
+}
+
+class B<T> {
+}
+
+class C<T, S> {
+}