Daniel D'Addario Chief TV CriticSPOILER ALERT: Do not read if you have not yet watched “Testimony,” the latest episode of “The Handmaid’s Tale.”Once again, Elisabeth Moss has been assigned a bravura bit of acting; once again, she’s delivered. The question “The Handmaid’s Tale” always seems to force is: Is that enough to keep us watching?On “Testimony,” the most recent episode of the fourth-season Hulu drama, Moss delivers a seven-minute speech, directly to camera, in a single unbroken shot.