ELAINE LIES and YOSHIFUMI TAKEMOTO PRIME Minister Shinzo Abe, Japan's longest-serving premier, has resigned because of poor health, ending a stint at the helm of the world's third-biggest economy during which he sought to revive growth and bolster its defences. "I cannot be prime minister if I cannot make the best decisions for the people. I have decided to step down from my post," Abe, 65, told a news conference. Abe has battled the disease ulcerative colitis for years and two recent hospital visits within a week had fanned questions on whether he could stay in the job until the…