Last night’s previews for “Kung-Fu Panda 4” resulted in receipts totaling $3.8 million. Almost everyone is predicting a $50 million 3-day opening for the animated sequel. In fact, we might get two $50 million grossing films this weekend. Denis Villeneuve’s “Dune: Part II” has some major legs — it made $6.4 million last night and cracked the $100 million domestic mark.