Expose remaining 'errors' in an unified dart:core.

tests/language/private_factory_resolution_negative_test.dart

Index: tests/language/private_factory_resolution_negative_test.dart
diff --git a/tests/language/private_factory_resolution_negative_test.dart b/tests/language/private_factory_resolution_negative_test.dart
deleted file mode 100644
index d7db72784c2376c429de451ae7f4e861e2c8666c..0000000000000000000000000000000000000000
--- a/tests/language/private_factory_resolution_negative_test.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2011, 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.
-
-class PrivateFactoryResolutionNegativeTest {
-
-  static testMain() {
-    new TypeError._uninstantiable();
-  }
-}
-
-main() {
-  PrivateFactoryResolutionNegativeTest.testMain();
-}