This allows the implementation of different stack scanning mechanisms in
V8 (e.g. conservative scanning) while re-using the stack walking API.

Change-Id: I9b9c3b8ffe5d527ca3f7105776821776b509b187
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2238194
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68457}