Also make ScopedList class Zone-agnostic and move it to src/utils.

Bug: v8:10506
Change-Id: Ibf0869566caa767809bdf95cb03c01e599613938
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2292234Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68825}