this is the stuff of dreams.Pop princess Miley Cyrus, 28, and Fleetwood Mac queen Stevie Nicks, 72, have teamed up for “Edge of Midnight (Midnight Sky Remix).”The cross-generational collaboration mashes up Cyrus’ current single “Midnight Sky” with Nicks’ 1981 classic from her debut solo album, “Bella Donna.”And from the moment it starts with that signature guitar riff — famously sampled by Destiny’s Child on “Bootylicious” — all the white-winged doves descend upon you, taking you to the edge of