The “Golden Age” in the name of Ayad Akhtar’s new play is both a sly nod to the pursuit of vast wealth and a reference to a specific time in history. The “Junk” that gets first billing in the title of this epic work should be a tipoff to what era that is: the gilded, grasping decade of the 1980s, when the idea of making piles of money by accumulating massive debt (via junk bonds and the like) first took hold.