This is a manual revert of 67cdacd9. Experiments have shown that inline
headers do bring real benefits and we won't be proceeding with inline
header removal.

Bug: v8:10749
Change-Id: Icd3d0b3926d0b7a24edb19d9f177e9c8818abe09
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2412174
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69915}