[scudo] Ensure proper allocator alignment in TSD test am: 43839dc421 am: f5a73051da am: 56b5fc25f2

Original change: https://android-review.googlesource.com/c/platform/external/scudo/+/1740873

Change-Id: Ia2acc15ebf80eb0a2f221699b8ab4c8839c545ed