BEIRUT — A pair of suicide bombers hit a crowded market in Baghdad on Thursday, Iraq’s civil defense agency said, killing at least 32 people, injuring more than 100 others and reigniting fears of a return to the days when such attacks were a daily occurrence in the Iraqi capital. The first of the bombers approached Tayaran Square, a major intersection in Baghdad’s downtown area near the Bab Sharqi open-air market for used clothing and surplus military gear. Sometime before 10 a.m., the attacker pretended to be sick to draw people to him, then detonated his explosives-laden vest, according to officials and local news reports.