Change MultipartFile.fromFile to MultipartFile.fromPath in pkg/http.

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';
 
 import 'package:pathos/path.dart' as path;
 import 'package:unittest/unittest.dart';
-import 'package:http/http.dart' as http;
-import 'package:http/src/utils.dart';
+import '../lib/http.dart' as http;
+import '../lib/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.
 Matcher bodyMatches(String pattern) => new _BodyMatches(pattern);
 
 class _BodyMatches extends BaseMatcher {
@@ skipping 194 matching lines @@
         --{{boundary}}
         content-type: application/octet-stream
         content-disposition: form-data; name="file"; filename="test-file"
 
         hello
         --{{boundary}}--
         '''));
     }).whenComplete(() => tempDir.delete(recursive: true)), completes);
   });
 }