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

tests/standalone/io/raw_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
+// OtherResources=certificates/untrusted_server_chain.pem
+// OtherResources=certificates/untrusted_server_key.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 607 matching lines @@
   testSimpleReadWrite(listenSecure: false,
                       connectSecure: false,
                       handshakeBeforeSecure: true,
                       postponeSecure: true,
                       dropReads: true);
   testPausedSecuringSubscription(false, false);
   testPausedSecuringSubscription(true, false);
   testPausedSecuringSubscription(false, true);
   testPausedSecuringSubscription(true, true);
 }