Well, I don't think it's something that anyone spends a great deal of time trying to eliminate. Beyond not breeding cryptorchids, of course. In those cases you know beyond doubt that the dog has two copies of the gene and will pass it along to *all* it's offspring.
Technically speaking, you could say that if two dogs ever have a cryptorchid amongst their offspring then you know that both parents are carriers. Well, in order to erradicate cryptorchidism you would need to eliminate them from the breeding pool. In reality that could mean an awful lot of otherwise good dogs excluded from breeding. Now if we were talking about a condition that severely impacted on the quality of life of the puppies, then that would be the responsible thing to do. But cryptorchidism isn't in that class at all. It just means that an affected individual has a high risk of developing cancer in the undescended testicle - but that is easily fixed by neutering. There is no other health implication.
In short, it is a condition that should not knowingly be increased in a dog breed - so you can't breed a cryptochid. But when it comes to attempts to eliminate disorders, breeder are rightly concentrating their efforts on things like cardiomyopathy, hip dysplasia and aortic stenosis that impact severely on the quality of life of individuals and the health of the breed as a whole. In an ideal world, perhaps greater efforts could be made to eliminate cryptorchidism, but I suspect the reality would be that the remaining gene pool was so small that we'd be introducing worse problems as a result
LOL - I would imagine that most breeders would wish to see that "thought to be an autosomal recessive trait" become a "it is definitely... and here's a means of testing for it" before taking such drastic measures too
