Remove duplicate test resource

tests/standalone/io/secure_unauthorized_test.dart

 // Copyright (c) 2013, 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.
 
 // OtherResources=certificates/untrusted_server_chain.pem
 // OtherResources=certificates/untrusted_server_key.pem
-// OtherResources=certificates/untrusted_server_chain.pem
 // OtherResources=certificates/trusted_certs.pem
 // OtherResources=secure_unauthorized_client.dart
 
 // This test verifies that failing secure connection attempts always complete
 // their returned future.
 
 import "package:expect/expect.dart";
 import "package:path/path.dart";
 import "dart:async";
 import "dart:io";
@@ skipping 36 matching lines @@
       }
     });
   }
 
   runServer().then((server) {
     clientProcess(server.port).then((_) {
       server.close();
     });
   });
 }