This CL makes CTZ (count trailing zeros) and POPCOUNT (count set bits),
which are optional ops in the raw machine assembler, available in CSA.
A fallback exists for the case that they are not available.

This CL also adds the 64 bit version of the mandatory CLZ (count
leading zeros) op available.

Change-Id: I53cd6738b8ede8bd5842a83bb1161299824d39c9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2742207Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Frank Emrich <emrich@google.com>
Cr-Commit-Position: refs/heads/master@{#73541}