The deal a Philadelphia firm was considering to acquire and renovate the historic Laura Street Trio and Barnett Bank Building in Downtown Jacksonville has fallen apart, according to sources. PMC Property Group Inc. of Philadelphia had entered an agreement to buy the trio, which includes the Marble Bank Building, the Florida Life and Bisbee Buildings, and the Barnett Bank Building from JDI Realty in Chicago in mid-September. The firm had a 60-day period in which to do due diligence, and decided not…