One less dependent load in InvokeBuiltin.

src/serialize.h

Index: src/serialize.h
diff --git a/src/serialize.h b/src/serialize.h
index ab2ae9f2964819cd1f80dc06810f4b7e2800086a..279bc583a3eb97f7ef138516d3869ae0466e55cb 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -503,7 +503,8 @@ class PartialSerializer : public Serializer {
     // unique ID, and deserializing several partial snapshots containing script
     // would cause dupes.
     ASSERT(!o->IsScript());
-    return o->IsString() || o->IsSharedFunctionInfo() || o->IsHeapNumber();
+    return o->IsString() || o->IsSharedFunctionInfo() ||
+           o->IsHeapNumber() || o->IsCode();
   }
 
  private: