This reverts commit 1c7618ab.

Reason for revert: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20-%20shared/10544

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,leszeks@chromium.org,dinfuehr@chromium.org

Change-Id: Iaf2362d8cd3a17d8410030aca0dd2250c5a0a7af
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2398533Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69762}