[builtins] make AsyncFunction constructor a subclass of Function

src/bootstrapper.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/base/ieee754.h"
 #include "src/code-stubs.h"
@@ skipping 2619 matching lines @@
 
     {
       PrototypeIterator iter(native_context->sloppy_async_function_map());
       Handle<JSObject> async_function_prototype(iter.GetCurrent<JSObject>());
 
       static const bool kUseStrictFunctionMap = true;
       Handle<JSFunction> async_function_constructor = InstallFunction(
           container, "AsyncFunction", JS_FUNCTION_TYPE, JSFunction::kSize,
           async_function_prototype, Builtins::kAsyncFunctionConstructor,
           kUseStrictFunctionMap);
-      async_function_constructor->set_prototype_or_initial_map(
-          native_context->sloppy_async_function_map());
       async_function_constructor->shared()->DontAdaptArguments();
       async_function_constructor->shared()->set_construct_stub(
           *isolate->builtins()->AsyncFunctionConstructor());
       async_function_constructor->shared()->set_length(1);
       InstallWithIntrinsicDefaultProto(isolate, async_function_constructor,
                                        Context::ASYNC_FUNCTION_FUNCTION_INDEX);
+      SetObjectPrototype(async_function_constructor,
+                         isolate->function_function());
 
       JSObject::AddProperty(
           async_function_prototype, factory->constructor_string(),
           async_function_constructor,
           static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY));
 
       JSFunction::SetPrototype(async_function_constructor,
                                async_function_prototype);
 
       Handle<JSFunction> async_function_next =
@@ skipping 1297 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8