There is no such thing as a sure thing in horse racing, but 'TDN Rising Star' Flightline (Tapit) will be bet as if Saturday's GI TVG Pacific Classic--a 'Win and You're In' qualifier for the GI Breeders' Cup Classic at Keeneland Nov. 5--is already the proverbial fait accompli. And why not, really? His four towering victories in as many trips to the races have come by an average winning margin of better than 13 lengths. His lowest Beyer Speed Figure is a downright pedestrian 105 earned for his debut just...