Fix CreateEmptyFunction to not share descriptor array.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index c65c68c2d75c37b0718b3e944967b22884957bb1..048a027349ce5316bb2e9f45fdc72be69efd20ef 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -484,8 +484,8 @@ Handle<JSFunction> Genesis::CreateEmptyFunction(Isolate* isolate) {
 
     global_context()->set_initial_object_prototype(*prototype);
     SetPrototype(object_fun, prototype);
-    object_function_map->
-      set_instance_descriptors(heap->empty_descriptor_array());
+    object_function_map->set_instance_descriptors(
+        heap->empty_descriptor_array());
   }
 
   // Allocate the empty function as the prototype for function ECMAScript
@@ -516,12 +516,10 @@ Handle<JSFunction> Genesis::CreateEmptyFunction(Isolate* isolate) {
   function_instance_map_writable_prototype_->set_prototype(*empty_function);
 
   // Allocate the function map first and then patch the prototype later
-  Handle<Map> empty_fm = factory->CopyMapDropDescriptors(
-      function_without_prototype_map);
-  empty_fm->set_instance_descriptors(
-      function_without_prototype_map->instance_descriptors());
-  empty_fm->set_prototype(global_context()->object_function()->prototype());
-  empty_function->set_map(*empty_fm);
+  Handle<Map> empty_function_map = CreateFunctionMap(DONT_ADD_PROTOTYPE);
+  empty_function_map->set_prototype(
+      global_context()->object_function()->prototype());
+  empty_function->set_map(*empty_function_map);
   return empty_function;
 }