We have to ensure that the memory location is sufficiently aligned to
store any object. This unbreaks the code for CHERI where using gsize
results in values that are only aligned to 8 bytes, but we need 16 byte
alignment for pointers. This is fully API/ABI compatible since amount
of padding before the actual allocation does not change for existing
architectures, only for CHERI.
Helps: https://gitlab.gnome.org/GNOME/glib/-/issues/2842