... in an uintptr index friendly way.

Bug: v8:8906, v8:4153
Change-Id: Ib06ac205453fe3ff653b4fb73194e1ab53ca0d00
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1891610
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64731}