Watching Yevgeny Mironov and Chulpan Khamatova embody Mikhail and Raisa Gorbachev in Alvis Hermanis’s bioplay “Gorbachev” was as gripping as the real events that unfurled in the background. Not only did the actors craft a powerful depiction of a symbiotic couple through most of their lives, but they changed costumes and did their own aging makeup in full view of the audience — including a remote one, as I watched a capture as part of the online Golden Mask festival of Russian theater. Exposing the artifice only made it more convincing.