The provided page allocator will serve all the memory requests done by the virtual
memory object.
This is a necessary cleanup before introducing BoundedPageAllocator.

Bug: v8:8096
Change-Id: I95477d67e5f532013322a991db3ee1a1f2e821e6
Reviewed-on: https://chromium-review.googlesource.com/1210122Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55703}