This is a port of src/components/gc that was added recently.

Differences:
- Added back bucketing to the page pool, as that guarantees that
  arenas used for specific types do not have their pages used by other
  arenas.
- Replaced base::flat_map with std::map. This may cause performance
  regressions when using PageMemoryRegionTree in hot paths. A
  vector-like representation may be used to fix such a regression

This reverts commit 656c68a7.

Bug: chromium:1056170
Change-Id: I638183c944255ebcaab47d2b94b1980d54479746
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2143814Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67080}