The function will be used to implement the web memory measurement API.

This adds an |allocated_bytes_at_last_gc| counter to each normal page.
The counter is updated by the sweeper.

Bug: chromium:1181269
Change-Id: If6612de06f373a839fce986c71ba3dfde4d9c9c2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2880534
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74446}