Even if the players were enjoying spending sixty rounds plinking away while the golems futilely chased them, I'd skip over most of that, because I would be bored out of my skull. When the players have declared tactics that guarantee a win, and I as DM determine that the monsters have no answer to these tactics--you win. You want to just sit there rolling dice and watching golem hit points tick inexorably down, do it on your own time.If the point of the battle is "will the Iron Golem ambush kill Prince Harry?" and there are three golems surrounding Harry at the start of the fight, and Harry has winged boots, then once Harry has escaped to open air and so have the PCs, there's no more dramatic question. At that point the encounter is trivialized. Either the party can hurt the golems or they can't, either the golems will chase them or they won't, but there is no need to do it in combat time if the players are no longer feeling excited. If they are enjoying spending sixty rounds plinking away while the golems roar and futilely chase after them on their horses, every round, then have at it.
Now, if there remains a question about how much damage the monsters do before they go, I am open to playing things out.