REUTERS MUMBAI, Sept 16 - Inordinately long toilets breaks or medical timeouts at critical moments could soon be a thing of the past in men's tennis with the ATP Tour planning to impose stricter rules, a source at the men's governing body told. The practice has long been a bugbear of players, most recently at the U.S. Open where Stefanos Tsitsipas was accused of gamesmanship by Andy Murray for taking a lengthy trip to the bathroom at a critical point in their first-round