BREAKING CHANGE: Remove === and !== in the VM compiler

tests/language/compile_time_constant_e_test.dart

 // Copyright (c) 2012, 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";
 
 class A {
   final x;
   final y;
   final z;
@@ skipping 20 matching lines @@
 const a8 = const A.named2();
 const a9 = const A.named2(x: 4, y: 3, z: 2, t: 1);
 const a10 = const A.named2(x: 1, y: 2, z: 3, t: 4);
 
 main() {
   Expect.equals(3, a1.x);
   Expect.equals(499, a1.y);
   Expect.equals(99, a1.z);
   Expect.equals(100, a1.t);
   Expect.equals("A 3 499 99 100", a1.toString());
-  Expect.isTrue(a1 === a2);
-  Expect.isTrue(a1 === a4);
-  Expect.isTrue(a1 === a5);
+  Expect.isTrue(identical(a1, a2));
+  Expect.isTrue(identical(a1, a4));
+  Expect.isTrue(identical(a1, a5));
 
   Expect.equals(1, a3.x);
   Expect.equals(2, a3.y);
   Expect.equals(3, a3.z);
   Expect.equals(4, a3.t);
   Expect.equals("A 1 2 3 4", a3.toString());
 
   Expect.equals(3, a6.x);
   Expect.equals(499, a6.y);
   Expect.equals(1, a6.z);
   Expect.equals(2, a6.t);
   Expect.equals("A 3 499 1 2", a6.toString());
 
   Expect.equals(3, a7.x);
   Expect.equals(407, a7.y);
   Expect.equals(7, a7.z);
   Expect.equals(null, a7.t);
   Expect.equals("A 3 407 7 null", a7.toString());
 
   Expect.equals(null, a8.x);
   Expect.equals(null, a8.y);
   Expect.equals(null, a8.y);
   Expect.equals(null, a8.t);
   Expect.equals("A null null null null", a8.toString());
 
-  Expect.isTrue(a3 === a9);
+  Expect.isTrue(identical(a3, a9));
 
   Expect.equals(4, a10.x);
   Expect.equals(3, a10.y);
   Expect.equals(2, a10.z);
   Expect.equals(1, a10.t);
   Expect.equals("A 4 3 2 1", a10.toString());
 }