This reverts commit 16e5dca3.

Reason for revert: https://chromium-review.googlesource.com/c/v8/v8/+/2565511 has to be reverted, and this was a follow-up to that

Original change's description:
> [compiler] Mark String as kNeverSerialized
>
> Bug: v8:7790
> Change-Id: I2deb462c3467f7239d55b0f295feed1de5ca1c2f
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2616198
> Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#72010}

TBR=neis@chromium.org,solanes@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:7790
Change-Id: Ie8b628fc5d0b0d90637515d7d3a2f1a9f64a0a09
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2629747Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72100}