Add test directive to include other files used by a test in its compiled output directory.

tests/standalone/io/secure_server_socket_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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
+// OtherResources=certificates/server_chain.pem
+// OtherResources=certificates/server_key.pem
+// OtherResources=certificates/trusted_certs.pem
 
 import "dart:async";
 import "dart:io";
 
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 
 InternetAddress HOST;
 
 String localFile(path) => Platform.script.resolve(path).toFilePath();
@@ skipping 214 matching lines @@
       for (bool cancelOnError in [true, false]) {
         if (server == null || client == null) {
           testSimpleConnectFail(server, client, cancelOnError);
         }
       }
     }
   }
   testServerListenAfterConnect();
   testSimpleReadWrite();
 }