On big endian 64 bit architectures, kHashFieldOffset is not word-aligned. 
This breaks the assumption in escape analysis that all fields are word-aligned. 
Fix this by not dematerializing such objects.

Alternative fix for https://chromium-review.googlesource.com/c/v8/v8/+/681335

Change-Id: I7d8e4c7934d9306cc06a614ae110e7cf7235394f
Reviewed-on: https://chromium-review.googlesource.com/681714
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48163}