VM: Fix bug in polymorphic inlining of recognized methods.

tests/language/vm/optimized_polymorphic_list_access_test.dart

+// Copyright (c) 2013, 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.
+// VMOptions=--optimization_counter_threshold=10
+
+import "package:expect/expect.dart";
+
+// Test correct polymorphic inlining of recognized methods like list access.
+
+test(arr) {
+  var r = 0;
+  for (var i = 0; i < 1; ++i) {
+    r += arr[0];
+  }
+  return r;
+}
+
+
+main() {
+  var a = new List<int>(1);
+  a[0] = 0;
+  var b = <int>[0];
+  Expect.equals(0, test(a));
+  Expect.equals(0, test(b));
+  for (var i = 0; i < 20; ++i) test(a);
+  Expect.equals(0, test(a));
+  Expect.equals(0, test(b));
+}