Varies based on person. I think a lot of devs don't play, and some might be considered admins rather than devs depending on your take. In the gaming industry a lot of companies consider anyone at the company "devs" and try to be inclusive. Outside, it means someone that writes code.
Example is one dev has a clear dev and play account. Another example would be bogie or PrincessJulie who clearly play and work on the same account.
When I've worked on games it's varied on if my play/work account is the same, usually depends on the company. At one I was the only person that did prod testing (live game) and it was honestly a miracle my account wasn't somehow permanently damaged with all the weird shit I did to it on back and front-end, but an end-game live account also made a perfect way to test how player accounts would react as I manipulated them a lot.
It's generally a good idea to separate play and work accounts though. Live testing is generally a bad idea and dangerous. Someone I worked with at another company tested something and broke the account of everyone online at the time in a game. Had to go into maintenance and fix all of them by hand running account data through a spreadsheet I made to fix data issues.
You'll usually have test environments running but sometimes you just need to test live. Torn definitely has a test environment but I'm sure some still needs testing here, and what accounts they use for it? Who knows. Maybe they clone player accounts and use those. It's also browser based so probably a lot less or at least different potential issues for live testing.