Reapply change to GVN all HFieldGet instructions.

tests/language/gvn_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.
 
 class A {
-  foo([a, b]) {
-    Expect.equals(0, a);
-    Expect.equals(1, b);
+  int x = 0;
+
+  foo(i) {
+    var start = x;
+    do {
+      x++;
+      i++;
+    } while (i != 10);
   }
 }
 
 main() {
-  A a = new A();
-  a.foo(a: 0, b: 1);
-  a.foo(b: 1, a: 0);
+  var a = new A();
+  a.foo(0);
+  Expect.equals(10, a.x);
 }