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

tests/language/vm/optimized_unique_selector_test.dart

Index: tests/language/vm/optimized_unique_selector_test.dart
diff --git a/tests/language/vm/optimized_unique_selector_test.dart b/tests/language/vm/optimized_unique_selector_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..bf0b5e4d71caebbc6e7df112c01205813ab6b07a
--- /dev/null
+++ b/tests/language/vm/optimized_unique_selector_test.dart
@@ -0,0 +1,42 @@
+// 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;
+}
+
+test1(obj) {
+  var res = 0;
+  for (var i = 0; i < 2; i++) {
+    obj._uniqueSelector();
+    res += obj.uniqueField;  // This load must not be hoisted out of the loop.
+  }
+  return res;
+}
+
+test2(obj) {
+  final objAlias = obj;
+  closure() => objAlias;
+  var res = 0;
+  for (var i = 0; i < 2; i++) {
+    obj._uniqueSelector();
+    res += objAlias.uniqueField;  // This load must not be hoisted out of the loop.
+  }
+  return res;
+}
+
+var foofoo_ = test1;
+
+main () {
+  Expect.equals(20, foofoo_(new A()));
+  Expect.throws(() => foofoo_(0));
+
+  foofoo_ = test2;
+
+  Expect.equals(20, foofoo_(new A()));
+  Expect.throws(() => foofoo_(0));
+}