This is a reland of commit e3096c31d6.
The one additional use of FLAG_turboshaft is also rewritten now.
Original change's description:
> [flags] Remove FLAG_* aliases
>
> This removes the deprecated FLAG_* aliases, and switches remaining uses
> to the new v8_flags syntax.
>
> R=jkummerow@chromium.org
>
> Bug: v8:12887
> Change-Id: Icde494a3819a9b1386c91e44f5d72a55666d9eae
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3952350
> Reviewed-by: Maya Lekova <mslekova@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#83686}
Bug: v8:12887
Change-Id: I978df89f51e11c9a101ff3c1e385b1eced697a74
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3953292
Reviewed-by: Marja Hölttä <marja@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83717}
444e6e3482