Reland r45243.

tests/language/vm/licm_constant_redefinition_vm_test.dart

+// Copyright (c) 2015, 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=100 --no-use-osr
+
+import "package:expect/expect.dart";
+
+class X {
+  final nested = [];
+
+  get length => nested.length;
+}
+
+loop(val) {
+  var sum = 0;
+  for (var i = 0; i < 10; i++) {
+    sum += val.length;
+  }
+  return sum;
+}
+
+// LoadField(LoadField(",", nested), length) should not be hoisted.
+// Otherwise it would crash.
+testRedef() => loop(",");
+
+main() {
+  // Provide polymorphic type feedback.
+  loop("");
+  loop(new X());
+
+  // Optimize loop with a constant argument.
+  for (var i = 0; i < 100; i++) {
+    testRedef();
+  }
+}