Simply put, you do not need to know flute and clarinet to get into college.
However, if you are a jazz-oriented person, going into a university setting with a knowledge of doubles can help you immensely in ensemble playing. It can also get you more gigs in pits for musicals and the like.
If you are an education person, knowing these instruments by having playing experience on them can be helpful too. It will make them easier to teach to young kids, because you'll know what they're going through as beginners.
However, if you are a jazz-oriented person, going into a university setting with a knowledge of doubles can help you immensely in ensemble playing. It can also get you more gigs in pits for musicals and the like.
If you are an education person, knowing these instruments by having playing experience on them can be helpful too. It will make them easier to teach to young kids, because you'll know what they're going through as beginners.