“Merry Xmas” to all, including the Jewish people who hold this holiday, and their Christmas traditions , near and dear. If you’ve ever been to a Chinese restaurant on Dec. 24 or visited the movie theater on Dec. 25 to find all the seats taken, chances are you’ve stumbled into the world of Christmas for Jews. The viral account “ Old Jewish Men ” is taking this fun, beloved tradition in stride, creating a T-shirt in collaboration with The Post that you can wear instead of an ugly Christmas sweater . The shirt ($35) features The Post’s red-and-black font, wishing...