Used include-what-you-use [1] to clean up cppgc API headers. The tool
does somewhat work but requires some cleanup afterwards as it cannot
nicely deal with `v8config.h` and the defines it generates.

[1] https://github.com/include-what-you-use/include-what-you-use/

Bug: chromium:1056170
Change-Id: I7b03797c615f8e033510fc959bbdb792d8b7a4ee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2907612Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74693}