The Kansas City Chiefs go through long, grueling drives during training camp that just about everyone has come to dread. They often take 18 or more plays and nobody is subbed out, instead forced to fight through utter exhaustion to the end.It’s not so hard on Patrick Mahomes, who mostly stands in the pocket to throw. But it’s brutal on everyone else.“Terrible,” Chiefs wide receiver Mecole Hardman acknowledged.The diabolical plan of Chiefs coach Andy Reid has a reason, though. The long-drive drills are designed to make the Chiefs learn how to win in the fourth quarter, and ultimately, how to win championships in the fourth quarter of the season. And it’s hard to dispute the results. They are 8-0 heading into Sunday’s matchup with the AFC West-rival Denver Broncos.“Coach Reid prepares us for those moments. He prepares us to be in those long drives,” said Mahomes, who practiced without any …