[runtime] Fix effect of setting .prototype on generator functions.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 258f9aea2c167e6b1ae9caf18fb7062f774ef09e..7c97c40f1b00a3ce0c7cb6fc15a0851cc5f73c1b 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11825,8 +11825,13 @@ void JSFunction::SetPrototype(Handle<JSFunction> function,
     new_map->SetConstructor(*value);
     new_map->set_non_instance_prototype(true);
     Isolate* isolate = new_map->GetIsolate();
+
     construct_prototype = handle(
-        function->context()->native_context()->initial_object_prototype(),
+        IsGeneratorFunction(function->shared()->kind())
+            ? function->context()
+                  ->native_context()
+                  ->initial_generator_prototype()
+            : function->context()->native_context()->initial_object_prototype(),
         isolate);
   } else {
     function->map()->set_non_instance_prototype(false);