Revert "Updated parser to produce error when trying to reinitialize final variables in class constr…

tests/language/final_attempt_reinitialization_test.dart

-// Copyright (c) 2017, 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.
-
-class Foo {
-  Foo(this.x); //# 01: compile-time error
-  final int x = 42;
-}
-
-class CoffeeShop {
-  final String shopName = "Coffee Lab";
-  CoffeeShop.name(String name) //# 02: compile-time error
-      : this.shopName = name; //# 02: compile-time error
-}
-
-void main() {
-  Foo f = new Foo(10); //# 01: compile-time error
-  CoffeeShop presidentialCoffee = //# 02: compile-time error
-      new CoffeeShop.name("Covfefe Lab"); //# 02: compile-time error
-}