In 2015, Miley Cyrus was coming off of the huge success of her post-Disney pop move Bangerz, the album that had “We Can’t Stop” and “Wrecking Ball.” She followed that record up with a hard zag: Miley Cyrus And Her Dead Petz, a wildly indulgent free-download surprise-release album that she largely recorded with the Flaming Lips. At the beginning of …