BY THE ASSOCIATED PRESS December 7, 2011 ISLAMABAD (AP) — Pakistan’s President Asif Ali Zardari traveled to Dubai for medical tests on his heart after falling ill, officials and associates said Wednesday, triggering Twitter-fueled rumors that the embattled leader may be stepping down. The president’s spokesman denied the speculation, which centered on the idea Zardari may use ill health as a pretext for stepping down under pressure from the country’s powerful military. “All these reports are untrue, imaginary and speculative,” Farhatullah Babar told The Associated Press. Zardari traveled to Dubai on Tuesday...