Comic actor with Everyman appeal, McLean Stevenson always seemed as if he would be comfortable on the 14th hole at a golf course, but not a restricted one. Tall and solidly built, albeit not without the illusion of a paunch, he was extremely popular as Col. Henry Blake on the TV series "M*A*S*H" and guest hosted "The Tonight Show Starring Johnny Carson" 58 times, but despite repeated attempts, failed to click with a series on which he was top banana. Stevenson had performed as a clown, but was not connected to show business when on a visit to New York he attended a party hosted by his cousin,