Tesla is reported to have abandoned a long-promised plan to offer an inexpensive electric car that investors have been counting on to drive its expansion in the mass market.The reported decision, which sent its shares sharply lower, represents a dramatic change of heart by Elon Musk, the company’s chief executive, who often has described Tesla’s primary mission as producing “affordable electric cars for the masses”. His first “master plan” for Tesla in 2006 called for the manufacture of luxury m...