This is a reland of 1c7618ab

The revert was due to an missing dependency in the incremental build,
fixed in https://crrev.com/c/2400987.

Original change's description:
> [serializer] Remove new space
>
> The new space is unused in the snapshot, as we convert all new objects
> to old space objects when serializing. This means we can get rid of
> the snapshot new space entirely, and as a result get rid of the write
> barrier checks.
>
> This also rejiggles the order of the general spaces enum so that the new
> spaces are at the end, and can be truncated off for the SnapshotSpace
> enum.
>
> As a drive by, fix a bug in an unrelated test-api test which this patch
> exposed.
>
> Change-Id: If67ff8be5bf03104a3ffae7df707c22460bba3a1
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2390762
> Commit-Queue: Leszek Swirski <leszeks@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#69761}

Tbr: jgruber@chromium.org,dinfuehr@chromium.org
Change-Id: I9fbc61a124fae09d12d6281baaca60eb6c39a6e5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2401420Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69785}