ERNIE BANKS, THE CHICAGO CUBS Hall of Famer, is known not only for what he did on the baseball field but also for what he never had the opportunity to do. Banks never played in post-season games or in the World Series. The other National League teams discarded the Cubs like chewing gum wrappers; the Cubs were permanent residents of the cellar. Yet every season Banks excelled as both a hitter and a fielder and never gave evidence of less effort. Recently in a radio interview. Banks was asked how he