Intel's contract manufacturing business has suffered a setback after tests with chipmaker Broadcom failed, three sources familiar with the matter told Reuters, dealing a blow to the company's turnaround efforts. The tests conducted by Broadcom involved sending silicon wafers - the foot-wide discs on which chips are printed - through Intel's most advanced manufacturing process known as 18A, the sources said. Broadcom received the wafers back from Intel last month. After its engineers and