This reverts commit 4ba3b515.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20TSAN%20-%20no-concurrent-marking/8900/overview

Original change's description:
> [heap] Disable map space with --future
>
> Bug: v8:12578
> Change-Id: If0253a2feb383d6ef313729bf99b489eb9436303
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3652794
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#80660}

Bug: v8:12578
Change-Id: I9ccfc2641b29539a29258a6517824cdd5a5709d5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3657432
Owners-Override: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#80664}