for "entries", i.e. indices into the backing store (as opposed to
"public indices" going into the hash function).
This improves consistency and compiler-enforced type safety; no change
in behavior is intended.

Change-Id: I25e57e3ddcf18a406e2dfbd66786b6980c4e9615
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1852768
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64317}