[iwyu] Include handles.h less.

src/api-experimental.h

 // Copyright 2015 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.
 
 #ifndef V8_API_EXPERIMENTAL_H_
 #define V8_API_EXPERIMENTAL_H_
 
-#include "src/handles.h"
-
 namespace v8 {
 namespace internal {
 class Code;
+template <typename T>
+class MaybeHandle;
 }  // internal;
 namespace experimental {
 class FastAccessorBuilder;
 }  // experimental
 
 namespace internal {
 namespace experimental {
 
 v8::internal::MaybeHandle<v8::internal::Code> BuildCodeFromFastAccessorBuilder(
     v8::experimental::FastAccessorBuilder* fast_handler);
 
 }  // namespace experimental
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_API_EXPERIMENTAL_H_