Would students who drop out before they take any exam be blacklisted by the (prestigious) university?
No. Students drop out of a class or school frequently. If it was recent - then you are likely still "admitted" and can register next term.
Or is it normal to be contacted by the university inciting the student to apply again?
I'm not sure they'll ask you to come back - they might, but it is up to you do work on getting back in.
I suggest checking your status on-line, or talk to someone in the registrar's office.
While a very prestigious school has a thousand students lined up behind you to take your place, it is likely that if they admitted you in the first place, they'll be happy to keep you. If you do it again, then they might think less of you.