Instead of actually allocating an objects just test the corner cases
around the page boundary by casting addresses.

Bug: v8:7984
Change-Id: I27615cc193d6f85abc91cfe898719a4a9b761f23
Reviewed-on: https://chromium-review.googlesource.com/1151114Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54717}