Make the sample tests run using the standard test configuration

samples/tests/samples/src/chat/HttpTest.dart

 // 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.
 
 #library("http_test.dart");
-#import("../../../chat/http.dart");
-#import("../../../../client/json/dart_json.dart");
-#import("../../../chat/chat_server_lib.dart");
+#import("../../../../chat/http.dart");
+#import("../../../../../client/json/dart_json.dart");
+#import("../../../../chat/chat_server_lib.dart");
 
 
 class TestServerMain {
   TestServerMain()
       : _statusPort = new ReceivePort(),
         _serverPort = null {
     new TestServer().spawn().then((SendPort port) {
       _serverPort = port;
     });
   }
@@ skipping 261 matching lines @@
 }
 
 
 void main() {
   testStartStop();
   testGET();
   testPOST(true);
   testPOST(false);
   test404();
 }