Change include guard to INCLUDE_V8_FORWARD_H_ from
INCLUDE_V8_LOCAL_HANDLES_H_.

Bug: v8:11965
Change-Id: I7a1a2fb3b5441b8f9cd733f89d19ccd5869c2287
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3162051
Auto-Submit: Dan Elphick <delphick@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76866}