Well Midget is a 19th century term for a proportionate dwarf, it came into use in 1865 and refered to dwarves and little people who toured the country in freak shows.
Medicaly dwarfism is a genetic or medical condition which results in an adult height of 4ft 10inches or less, in both men and women.
So no in answer to your question Wolverine isn't a midget, hes just short for a human male.
Also Midget is now deemed an offensive term as far as people with the medical condition are concerned, how do I know this?
Tis called google! 😛