This is a reland of 40b062ce. Known
existing problems have been fixed, see https://crbug.com/v8/12330.

Original change's description:
> [future] Use mid-tier regalloc for huge functions
>
> Stage the --turbo-use-mid-tier-regalloc-for-huge-functions behind
> --future.
>
> R=thibaudm@chromium.org
>
> Bug: v8:12287, v8:12320
> Change-Id: I7145ca1b022bfdcb0b61d6666daf855f14cbc4ce
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3236547
> Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
> Commit-Queue: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#77549}

Bug: v8:12287, v8:12320, v8:12330
Change-Id: I90eb2cb54b42fca77c1e3db9c18b20080f0d9338
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3347822Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78635}