Also deleted iwyu script that was not maintained, and deleted some options that made the script more complex. Bug: none Change-Id: I39d8eaa37f12c72ddc127ae145e6a3a80f328316 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/251384 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Commit-Queue: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/main@{#35966}