To the outside world, Hollywood might ooze effortless glamour, but just about anyone who makes movies will say the process is a long grind, and a continual blow to the ego and bank account. That might explain why two films that embody the inherent struggle of show business – “Birdman” and “Boyhood” – are top contenders for best picture at Sunday’s 87th Academy Awards. Experts say, even if “Birdman” has the slightest edge, the race is one of the hardest to predict in years. And they say it adds welcome suspense to Hollywood’s annual climax, the largest televised event in the United States outside of the sports world.