AOT: Fix bug in receiver type propagation after unique selector calls.

tests/language/vm/optimized_unique_selector_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.
+
+import "package:expect/expect.dart";
+
+class A {
+  _uniqueSelector() { }
+  final uniqueField = 10;
+}
+
+foofoo(obj) {
+    var res = 0;

[Vyacheslav Egorov (Google), 2016/11/16 12:55:06]

incorrect indentation 

[Florian Schneider, 2016/11/16 17:55:18]

Done.

+    for (var i = 0; i < 2; i++) {
+      obj._uniqueSelector();
+      res += obj.uniqueField;  // This load must not be hoisted out of the loop.
+    }
+    return res;
+}
+
+var foofoo_ = foofoo;
+
+main () {
+  Expect.equals(20, foofoo_(new A()));
+  Expect.throws(() => foofoo_(0));
+}