CR 400.6: Support choosing between contradictory zone changes

> Exquisite Archangel has an ability which reads “If you would lose the game,
instead exile Exquisite Archangel and your life total becomes equal to your starting life
total.” A spell deals 5 damage to a player with 5 life and 5 damage to an Exquisite
Archangel under that player’s control. As state-based actions are performed, that player’s
life total becomes equal to their starting life total, and that player chooses whether Exquisite
Archangel moves to its owner’s graveyard or to exile.