Dallas’ mayor, Michael S. Rawlings, testified this month to a state oversight board that his city appeared to be “walking into the fan blades” of municipal bankruptcy. Rawlings added that it is ironic that Dallas has the fastest economic growth of the nation’s 13 largest cities. Its streets hum with supersize cars and its skyline bristles with cranes. Hundreds of multinational corporations have chosen Dallas for their headquarters, most recently Jacobs Engineering, which is moving to low-tax Texas from pricey Pasadena, Calif.