PHILADELPHIA — It has been 24 minutes of ugly offensive basketball for the 76ers, two fourth quarters in which they managed a grand total of 30 points.  Twelve points in the final quarter of Game 2, 18 in the final quarter of Game 3. Both were winnable games that were lost because of Philadelphia’s offensive ineptitude, and now it will have to make NBA playoff history as the first team to rally from 3-0 down to advance.  Jalen Brunson drives on V.J. Edgecombe during the second quarter of the Knicks Game 3 win over the 76ers in Philadelphia. Charles Wenzelberg / New York Post At least, that’s how the 76ers see it. It wasn’t the Knicks defense that did them in. It was their own doing.  “We’re not making shots, we’re getting a lot of looks,” rookie VJ Edgecombe said Saturday. “We just watched the film. We’re generating a lot of good looks. Nothing is going in for us.”  In Game 2, the 76ers shot 4-for-19 from the field over the final 12 minutes. In Game 3, it was 7-for-20.…