Whenever PagedNewSpace allocates a page, the page is added to the free
list. Preallocating pages on space initialization means the pages are
added to the free list before the map for free space is initialized.
Then, when allocating from the free list, a DCHECK fails
(free-list.cc:508).

This CL delays page preallocation until `EnsureCurrentCapacity` is
called. When using PagedNewSpace, we will call this method from
`Heap::CreateHeapObjects` after the maps are allocated and before any
allocations in new space are attempted.

Bug: v8:12612
Change-Id: I33f825ddd831640b12e4c0f7b849262a335df51e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3780541Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81919}