This reverts commit 0e4554b4.

Reason for revert: Breaks due to read-only flags https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Mac%20-%20arm64%20-%20debug%20builder/3926/overview

Original change's description:
> [baseline] Enable concurrent sparkplug on future
>
> Bug: v8:12054
> Change-Id: I9d5040c806232ecbe71c26b7d65acbc8005bbd00
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3233139
> Commit-Queue: Victor Gomes <victorgomes@chromium.org>
> Reviewed-by: Leszek Swirski <leszeks@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#77842}

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

Change-Id: I25bbe7f38d87fcc13931782d26cd6b75bba50848
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:12054
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3275555Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77843}