No idea if they've ever had official ones, but I'd bet the ones on Amazon are nothing to do with Asahi.
Amazon is absolutely rammed with clothes and books that infringe trademarks, but, as I said, their policy is pretty much "accept almost everything, but wash their hands as soon as they're challenged". If Superdry contacted Amazon, those t-shirts would likely be gone within a day.
It's a different situation to City, and there's also a difference in degree between someone flogging half a dozen t-shirts a year on Amazon, and a training shirt that is regularly seen on TV by millions, and will appear in online media on a regular basis. A cynic might suggest that part of that difference is that Superdry wouldn't get any publicity from asking Amazon to stop the trader selling those t-shirts.