PHILADELPHIA — A Philadelphia firefighter was killed and four others were injured in an early-morning building collapse that has devastated the Fire Department and left a neighborhood shaken. A city building inspector was also injured in the collapse in the city’s Fairhill section, which followed a fire at a popular pizza shop that appears to have had construction done without permits in recent years. The firefighter who was killed was not immediately identified, pending notification of family, but First Deputy Fire Commissioner Craig Murphy described them as a 27-year veteran. “It’s going to …