Get rid of all the library tags.

test/upgrade/hosted/upgrade_removed_constraints_test.dart

Index: test/upgrade/hosted/upgrade_removed_constraints_test.dart
diff --git a/test/upgrade/hosted/upgrade_removed_constraints_test.dart b/test/upgrade/hosted/upgrade_removed_constraints_test.dart
index b8ec8371a70297dac4376843a2ad013ef22b1a97..b6f1c368b5f2f62309b48882799e41091ec92c51 100644
--- a/test/upgrade/hosted/upgrade_removed_constraints_test.dart
+++ b/test/upgrade/hosted/upgrade_removed_constraints_test.dart
@@ -2,8 +2,6 @@
 // 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 pub_tests;
-
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';