Migrate test block 30 + corelib portion of block 31 to Dart 2.0.

tests/corelib_2/uri_parameters_all_test.dart

 // Copyright (c) 2015, 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.
 
 import "package:expect/expect.dart";
 import 'dart:convert';
 
 main() {
   testAll(["a", "b", "c"]);
   testAll([""]);
@@ skipping 31 matching lines @@
   var params = uri.queryParametersAll;
   for (var k in results.keys) {
     Expect.listEquals(results[k], params[k]);
   }
   uri = new Uri(scheme: "foo", path: "bar", queryParameters: results);
   params = uri.queryParametersAll;
   for (var k in results.keys) {
     Expect.listEquals(results[k], params[k]);
   }
 }