Fix mutual exclusivity between `AUTO_CTOR_DTOR` and `ISO_DTOR_CLEANUP` as described in the comments here: https://github.com/struct/isoalloc/pull/128#pullrequestreview-1091854336
Fix mutual exclusivity between
AUTO_CTOR_DTORandISO_DTOR_CLEANUPas described in the comments here:#128 (review)