... and use it for allocation of FixedArray-based objects with custom maps.

Change-Id: Id31d05cf506e3607210fe7fdaf05f55053de5e2a
Reviewed-on: https://chromium-review.googlesource.com/789113Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49622}