fails:Bignum#<=> with an Object calls #coerce on other
fails:Bignum#<=> with an Object returns nil if #coerce raises an exception
fails:Bignum#<=> with an Object raises an exception if #coerce raises a non-StandardError exception
fails:Bignum#<=> with an Object returns nil if #coerce does not return an Array
fails:Bignum#<=> with an Object returns -1 if the coerced value is larger
fails:Bignum#<=> with an Object returns 0 if the coerced value is equal
fails:Bignum#<=> with an Object returns 1 if the coerced value is smaller
