Merge the dart:uri library into dart:core and update the Uri class

pkg/http/test/utils.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.
 
 library test_utils;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:json' as json;
-import 'dart:uri';
 
 import 'package:http/http.dart' as http;
 import 'package:http/src/byte_stream.dart';
 import 'package:http/src/utils.dart';
 import 'package:unittest/unittest.dart';
 
 import 'safe_http_server.dart';
 
 /// The current server instance.
 HttpServer _server;
@@ skipping 180 matching lines @@
 const isSocketIOException = const _SocketIOException();
 
 /// A matcher for functions that throw SocketIOException.
 const Matcher throwsSocketIOException =
     const Throws(isSocketIOException);
 
 class _SocketIOException extends TypeMatcher {
   const _SocketIOException() : super("SocketIOException");
   bool matches(item, MatchState matchState) => item is SocketIOException;
 }