Incl. random handler-related cleanups.

Change-Id: I0a80e515c44aaf57a1834ee8ffa9cd47a31ea7be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2398518
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70155}