This CL is part of a series that adds the C++ implementation of
SwissNameDictionary, a deterministic property backing store based on
Swiss Tables.

This CL adds swiss-hash-table-helpers.h, which contains helpers
that are mostly independent from a particular swiss table
implementation (like SwissNameDIctionary) and can therefore be re-used
by potential other Swiss Table implementations in the future. As a
consequence of that, those helpers are largely taken unchanged from
Abseil.

Bug: v8:11388
Change-Id: I27636731c2166cb10240b847a1d7df0412aa0a33
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2687752
Commit-Queue: Frank Emrich <emrich@google.com>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72734}