Mobs immediately forget where the player is if out of eyesight

Mobs immediately forget where the player is when they do not have a direct line of sight. This makes it difficult for them to follow and makes the game too easy for the player. Mobs should continue to the last known player location before randomly wandering away. This also applies to baby zombies that are up against a one-block step.

Oops: MCPE-32815