This reverts commit 5e16d853.

Reason for revert: TSAN https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20no-concurrent-marking/6432/overview

Original change's description:
> [SharedFunctionInfo] Add available_baseline_code flag
>
> Checks that flags1 are ReadOnly after SFI is finalised.
>
> Bug: v8:12054
> Change-Id: Ia2518b8f136a81aa076fd429bf4fcaf742a314e3
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3263897
> Commit-Queue: Victor Gomes <victorgomes@chromium.org>
> Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#77816}

TBR=leszeks@chromium.org,v8-scoped@luci-project-accounts.iam.gserviceaccount.com,victorgomes@chromium.org,nicohartmann@chromium.org

Change-Id: Ifb28601a6f6dbe24b38e2e9ea2a5a7e576c0c511
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:12054
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3270545Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Owners-Override: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77818}