Fix a dartc error for pkg/http/multipart_test.

pkg/http/test/multipart_test.dart

 // Copyright (c) 2012, 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 multipart_test;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:utf';
 
-// TODO(nweiz): get rid of this import before packaging this
-import '../../../tests/utils/test_utils.dart';
 import 'package:unittest/unittest.dart';
 import 'package:http/http.dart' as http;
 import 'package:http/src/utils.dart';
 
 import 'utils.dart';
 
 /// A matcher that validates the body of a multipart request after finalization.
 /// The string "{{boundary}}" in [pattern] will be replaced by the boundary
 /// string for the request, and LF newlines will be replaced with CRLF.
 /// Indentation will be normalized.
@@ skipping 175 matching lines @@
     expect(request, bodyMatches('''
         --{{boundary}}
         content-type: application/octet-stream
         content-disposition: form-data; name="file"
 
         hello
         --{{boundary}}--
         '''));
   });
 }