This reverts commit e3a42cfd.

Reason for revert: Breaking compilation on "V8 Linux - noi18n - debug" bot, see https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Linux%20-%20noi18n%20-%20debug/23170

Original change's description:
> [cleanup] Remove Heap::kOldSpaceRoots constant
> 
> ... in favour of RootsTable::IsImmortalImmovable().
> 
> Bug: v8:8238
> Change-Id: Ic8434a1658b9ba982a93dd268dbfe52a6cc5c6a2
> Reviewed-on: https://chromium-review.googlesource.com/c/1270582
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#56472}

TBR=ulan@chromium.org,yangguo@chromium.org,ishell@chromium.org

Change-Id: I3a160716c9d558f4ab89b45a7257a461733f7273
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:8238
Reviewed-on: https://chromium-review.googlesource.com/c/1270588Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56475}