WHEN A YOUNG man can lose a fight and still earn as much as $13 million for 91 seconds of being punched, it may be unrealistic to expect that potentially grave health risks will deter the continuation of professional boxing. Even though few professional boxers ever stand to reap the financial rewards of current heavyweight champion Mike Tyson or challenger Michael Spinks (whom Tyson knocked out in about a minute and a half), their success seems to keep the dream alive for some youngsters. However, amateur boxing is about to come under closer scrutiny again. Juan Antonio Samarach, president of the International Olympic Committee (IOC), supports boxing but announced at the conclusion of the Games in Seoul that the IOC is studying a suggestion to drop it as an Olympic sport. A similar study was made in 1984. The IOC's Executive Committee reviewed the status of boxing at its meeting