... to avoid additional indirection on every access.

Drive-by: given that AccessorInfo class now has a custom body visitor
it's no longer necessary to encode flags field as Smi.

Bug: v8:12949
Change-Id: I30eabee3cbc5ded2bf3f050dfe22208713a764bf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3701590Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81237}