Concurrent Ruby : `AtomicReference#update` livelocks when the stored value is `Float::NAN`

Summary Concurrent::AtomicReferenceupdate can enter a permanent busy retry loop when the current value is Float::NAN. The issue is caused by the interaction between: - AtomicReferenceupdate, which retries until compareandsetoldvalue, newvalue succeeds. - Numeric compareandset, which checks old ==...