The Palm Springs Spa (now The Spa Resort and Hotel) will be demolished within the next 18 months. The Agua Caliente Band of Cahuilla Indians  confirmed this at a recent meeting withthe Palm Springs City Council. The  hotel is scheduled to close on July 8th. Apparently, this is a done deal.      Photo: Julius Shulman,  Getty Research Institute       Architects Donald Wexler, Richard Harrison and William Cody teamed up to design Palm Springs Spa Hotel in 1958.   Those Nelson benches are really cool. Too bad they aren't there anymore.   Photo: Julius Shulman,  Getty Research Institute       Photo: Julius Shulman,  Getty Research Institute       The reflecting pool and Architectural Pottery are long gone.           It's easy to miss, but there's an insane John Mason ceramic installation behind the bushes, to the left of the walkway.       The Mason sculptures can be seen in this cropped shot from 1961....