When inlined allocations are disabled, the space->limit() does not point to the
end of the current page. Instead, it points to the current allocation pointer so
is the same as space->top().

See how the limit is computed, if heap()->inline_allocation_disabled(), then the
limit will be the same as the requested allocation area:

```
Address SpaceWithLinearArea::ComputeLimit(Address start, Address end,
                                          size_t min_size) {
  DCHECK_GE(end - start, min_size);

  if (heap()->inline_allocation_disabled()) {
    // Fit the requested area exactly.
    return start + min_size;
  } else if (SupportsInlineAllocation() && AllocationObserversActive()) {
    // ...
  } else {
    // The entire node can be used as the linear allocation area.
    return end;
  }
}
```

If we want to simulate filling up a whole page in the new space, we can instead
look at the ToSpace's page_high() which will be the end of the current page in
which we're allocating.

Bug: v8:9906
Change-Id: I81113d151bc083cd22d17ea1a4fbae7fef9dff6d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1886914Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#64612}