Fix http_server_response_test.dart not to use snapshots as its data.

tests/standalone/io/http_server_response_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=http_server_response_test.dart
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:typed_data";
 
+// Platform.script may refer to a AOT or JIT snapshot, which are significantly
+// larger.
+File scriptSource = new File(
+    Platform.script.resolve("http_server_response_test.dart").toFilePath());
+
 void testServerRequest(void handler(server, request),
                        {int bytes,
                         bool closeClient}) {
   HttpServer.bind("127.0.0.1", 0).then((server) {
     server.defaultResponseHeaders.clear();
     server.listen((request) {
       handler(server, request);
     });
 
     var client = new HttpClient();
@@ skipping 49 matching lines @@
     request.response.done.then((_) {
       server.close();
     });
     request.response.contentLength = 0;
     request.response.close();
   });
 }
 
 
 void testResponseAddStream() {
-  File file = new File(Platform.script.toFilePath());
+  File file = scriptSource;
   int bytes = file.lengthSync();
 
   testServerRequest((server, request) {
     request.response.addStream(file.openRead())
         .then((response) {
           response.close();
           response.done.then((_) => server.close());
         });
   }, bytes: bytes);
 
@@ skipping 28 matching lines @@
   testServerRequest((server, request) {
     new File("__nonexistent_file_").openRead().pipe(request.response)
         .catchError((e) {
           server.close();
         });
   });
 }
 
 
 void testResponseAddStreamClosed() {
-  File file = new File(Platform.script.toFilePath());
+  File file = scriptSource;
   testServerRequest((server, request) {
     request.response.addStream(file.openRead())
         .then((response) {
           response.close();
           response.done.then((_) => server.close());
         });
   }, closeClient: true);
 
   testServerRequest((server, request) {
     int count = 0;
     write() {
       request.response.addStream(file.openRead())
           .then((response) {
             request.response.write("sync data");
             count++;
             if (count < 1000) {
               write();
             } else {
               response.close();
               response.done.then((_) => server.close());
             }
           });
     }
     write();
   }, closeClient: true);
 }
 
 
 void testResponseAddClosed() {
-  File file = new File(Platform.script.toFilePath());
+  File file = scriptSource;
   testServerRequest((server, request) {
     request.response.add(file.readAsBytesSync());
     request.response.close();
     request.response.done.then((_) => server.close());
   }, closeClient: true);
 
   testServerRequest((server, request) {
     for (int i = 0; i < 1000; i++) {
       request.response.add(file.readAsBytesSync());
     }
@@ skipping 131 matching lines @@
   testResponseDone();
   testResponseAddStream();
   testResponseAddStreamClosed();
   testResponseAddClosed();
   testBadResponseAdd();
   testBadResponseClose();
   testIgnoreRequestData();
   testBadHeaders();
   testWriteCharCode();
 }