Update language.status and rewrite two tests

tests/language/constructor2_negative_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.
-// Check that all final instance fields of a class are initialized by constructors.
-
-
-class Klass {
-  Klass(var v): field_ = v { }
-  final uninitializedFinalField_;
-  var field_;
-}
-
-
-class Constructor2NegativeTest {
-  static testMain() {
-    var o = new Klass(5);
-  }
-}
-
-main() {
-  Constructor2NegativeTest.testMain();
-}