By ERIC SCHMITT
WASHINGTON — In just the past few days, the Islamic State’s evolving brand of terrorism has revealed its deadly, shifting faces. n Istanbul last week, Turkish officials say, militants guided by the Islamic State conducted a coordinated suicide attack on the city’s main airport. In Bangladesh on Friday, a local extremist group that has pledged loyalty to the Islamic State butchered diners in a restaurant. And in Baghdad on Sunday, the Islamic State claimed responsibility for a bombing that killed more than 140 people.