Fix deferred loading code invalidation when both unoptimized and optimized code of the same functio…

tests/language/deferred_optimized_test.dart

+// Copyright (c) 2014, 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 --no-use-inlining
+
+// Declares foo that returns 42.
+import "deferred_constraints_lib2.dart" deferred as lib;
+
+import 'package:expect/expect.dart';
+
+bool libLoaded = false;
+
+main() {
+  Expect.equals(88, heyhey());
+
+  for (int i = 0; i < 30; i++) {
+    heyhey();
+  }
+
+  lib.loadLibrary().then((_) {
+    libLoaded = true;
+    Expect.equals(42, heyhey());
+  });
+}
+
+
+heyhey() => barbar();
+
+
+barbar() {
+  if (libLoaded) {
+    // Returns 42.
+    return lib.foo();
+  }
+  return 88;
+}