A couple of allocation were still going to new space. Since objects
allocated during isolate initialization are long living anyway, we
should pretenure them.

This also untangles preallocating pages in the paged new space.

Bug: v8:12612
Change-Id: Ib63ff4445930afa5969464e6adaef85b314e95ff
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3782802Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81903}