PHILADELPHIA — The first attempt fell 1:21 after the opening tip. The next dropped 1:10 later. On the ensuing possession, Jalen Brunson missed a 3-pointer. What was special about that, you might ask? It was a rarity Sunday for these rampaging Knicks, who returned to the Eastern Conference finals with a dominant 144-114 victory at Xfinity Mobile Arena on Mother’s Day. They made their next nine 3-point attempts, on their way to hitting an incredible 25 from distance, a franchise postseason record that also equaled the all-time NBA mark set by the Bucks (2021) and Cavaliers (2016). They equaled another NBA playoff record by hitting 11 3s in the first quarter and 18 in the first half, for their seventh straight win of this postseason. “It’s definitely special. I didn’t even know, honestly,” Miles McBride said, referring to the record-matching 3-point shooting display. “To have anything like that on your name is a legacy you want.” Jalen Brunson hits a 3-pointer during the Knicks’ May 10 game against the 76ers.…