In South Korea, as in many other nations, military service by men of a certain age is compulsory — and over there, you have to serve between the ages of 20 and 30. A nice-sized window — but that time does go fast when you’re pursing a professional baseball career. Cleveland Indians outfielder Shin-Soo Choo, 28, was nearing the end of his window and facing the possibility of having to take time off from the majors to serve his nation. But with the South Korean team’s 9-3 win against Taiwan in the final of the Asian Games on Friday, Choo…