The Alassane Ouattara stadium rises like a piece of sculpture from the dusty brown earth north of Ivory Coast’s largest city, its undulating roof and white columns towering over the empty landscape like a spaceship that has dropped onto a uninhabited planet. On Sunday, the three-and-a-half-year-old stadium will host its signature moment, when the national soccer teams of Ivory Coast and Nigeria compete in the final of Africa’s biggest sporting event, in front of tens of thousands of fans chanting and cheering in a stadium financed and built by China.…