No it isn’t I have just noticed one in Manchester (UK), see the attached photo.
I did some research by myself and according to that and your comments, I really think these vomitoriums are particularly available in Switzerland.
In very traditional restaurants or in restaurants that are visited by a lot of students, a lot of Swiss restaurants have them. They are mounted on the wall approximately 1.50 meters above the floor and they have an extra strong flush and large drain. In Switzerland there are a lot of students associations (Studentenverbindungen in German) that regularly have meetings in restaurants. During these meetings they drink really a lot of beer and it is very common that some of them have to vomit because of too much alcohol. To prevent a congested toilet, these restaurants have adapted and built-in these special-purpose vomitoriums.
In other countries the student association doesn’t have such a strong and old tradition and therefore it is not necessary to install vomitoriums in restaurants.
Credit:stackoverflow.com‘