Mark as prototype only after instantiating the function

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 7729c2018dd5bc3e5e0308f619cc996aae1654d3..cfac520acc6092074855baece99b4e1cf0f7decc 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -4451,8 +4451,8 @@ bool Map::is_extensible() {
 }
 
 
-void Map::mark_prototype_map() {
-  set_bit_field2(IsPrototypeMapBits::update(bit_field2(), true));
+void Map::set_is_prototype_map(bool value) {
+  set_bit_field2(IsPrototypeMapBits::update(bit_field2(), value));
 }
 
 bool Map::is_prototype_map() {
@@ -5940,11 +5940,6 @@ Map* JSFunction::initial_map() {
 }
 
 
-void JSFunction::set_initial_map(Map* value) {
-  set_prototype_or_initial_map(value);
-}
-
-
 bool JSFunction::has_initial_map() {
   return prototype_or_initial_map()->IsMap();
 }