[builtins] Move more files into v8_builtins_generators source set

src/builtins/builtins-forin.h

-
-// Copyright 2017 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/code-stub-assembler.h"
-
-namespace v8 {
-namespace internal {
-
-class ForInBuiltinsAssembler : public CodeStubAssembler {
- public:
-  explicit ForInBuiltinsAssembler(compiler::CodeAssemblerState* state)
-      : CodeStubAssembler(state) {}
-
-  std::tuple<Node*, Node*, Node*> EmitForInPrepare(Node* object, Node* context,
-                                                   Label* call_runtime,
-                                                   Label* nothing_to_iterate);
-
-  Node* ForInFilter(Node* key, Node* object, Node* context);
-
- private:
-  // Get the enumerable length from |map| and return the result as a Smi.
-  Node* EnumLength(Node* map);
-  void CheckPrototypeEnumCache(Node* receiver, Node* map, Label* use_cache,
-                               Label* use_runtime);
-  // Check the cache validity for |receiver|. Branch to |use_cache| if
-  // the cache is valid, otherwise branch to |use_runtime|.
-  void CheckEnumCache(Node* receiver, Label* use_cache,
-                      Label* nothing_to_iterate, Label* use_runtime);
-};
-
-}  // namespace internal
-}  // namespace v8