The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
A place like that would be a Torture Cellar, but that trope may better fit the droid torture scene in Jabba's Palace two films later. I initially saw the sandcrawler as more of just a creepy Collector of the Strange type deal.
On the other hand, you're right; to droids, the sandcrawler would be a straight example of a Torture Cellar, so I think some Fridge Horror may be at play here, too. Modern audiences are probably far more likely to see this as a Torture Cellar thanks to how far sci-fi—and this franchise specifically—has come with the "are machines people?" debate since the film was released.
“Quitters never lose!”
Is there a trope for a scene where a character goes to a place and finds everyone is being tortured and/or enslaved? Like the robots in the Jawa sandcrawler from Star Wars: A New Hope?