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

tests/lib/mirrors/mirrors_test.dart

 // Copyright (c) 2011, 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.
 
 // TODO(rmacnak): Move the existing mirror tests here (a place for
 // cross-implementation tests).
 
 library MirrorsTest;
 import "dart:mirrors";
 import "../../../pkg/unittest/lib/unittest.dart";
-import 'dart:uri';
 
 var topLevelField;
 
 class Class<T> {
   Class() { this.field = "default value"; }
   Class.withInitialValue(this.field);
   var field;
   static var staticField;
   m(a, b, c) => {"a": a, "b": b, "c": c};
 }
@@ skipping 192 matching lines @@
       (Uri uri) => uri.path.endsWith('/mirrors_test.dart'));
   });
   test("Test dart library uri", () {
     testLibraryUri("test", (Uri uri) => uri == Uri.parse('dart:core'));
   });
 }
 
 main() {
   mainWithArgument(isDart2js: false);
 }