Reapply "Make Map constructors return LinkedHashMap."

tests/standalone/io/http_detach_socket_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
 
 import "package:expect/expect.dart";
@@ skipping 60 matching lines @@
 void testClientDetachSocket() {
   ServerSocket.bind("127.0.0.1", 0).then((server) {
     server.listen((socket) {
       socket.write("HTTP/1.1 200 OK\r\n"
                        "\r\n"
                        "Test!");
       var body = new StringBuffer();
       socket.listen(
         (data) => body.write(new String.fromCharCodes(data)),
         onDone: () {
-          Expect.equals("GET / HTTP/1.1\r\n"
-                        "accept-encoding: gzip\r\n"
-                        "content-length: 0\r\n"
-                        "host: 127.0.0.1:${server.port}\r\n\r\n"
-                        "Some data",
-                        body.toString());
+          List<String> lines = body.toString().split("\r\n");
+          Expect.equals(6, lines.length);
+          Expect.equals("GET / HTTP/1.1", lines[0]);
+          Expect.equals("", lines[4]);
+          Expect.equals("Some data", lines[5]);
+          lines.sort();  // Lines 1-3 becomes 3-5 in a fixed order.
+          Expect.equals("accept-encoding: gzip", lines[3]);
+          Expect.equals("content-length: 0", lines[4]);
+          Expect.equals("host: 127.0.0.1:${server.port}", lines[5]);
           socket.close();
         });
       server.close();
     });
 
     var client = new HttpClient();
     client.userAgent = null;
     client.get("127.0.0.1", server.port, "/")
       .then((request) => request.close())
       .then((response) {
@@ skipping 11 matching lines @@
         });
       });
   });
 }
 
 void main() {
   testServerDetachSocket();
   testBadServerDetachSocket();
   testClientDetachSocket();
 }