"Cast as though it had flash" effects need to be reworked

[awjackson]

If there are several effects that would allow a player to cast a spell as though it had flash, xmage should give the player a choice of which one to use, and cards should be able to distinguish which one was chosen. For example, if you have a [[Vedalken Orrery]] on the battlefield and an [[Armor of Thorns]] in hand, you should be able cast the Armor at instant speed using the Orrery's ability rather than the Armor's own ability and not have to sacrifice the Amor at the end of your turn.

Relatedly, if you cast Armor of Thorns via an effect that tells you to cast a spell (such as cascade or [[Chandra, Torch of Defiance]]'s first loyalty ability) it is incorrectly treated like casting it with its as-though-flash ability, meaning you will have to sacrifice it.

[github-actions[bot]]

Vedalken Orrery - (Gatherer) (Scryfall) (EDHREC)

{4} Artifact You may cast spells as though they had flash.

Armor of Thorns - (Gatherer) (Scryfall) (EDHREC)

{1}{G} Enchantment — Aura You may cast Armor of Thorns as though it had flash. If you cast it any time a sorcery couldn't have been cast, the controller of the permanent it becomes sacrifices it at the beginning of the next cleanup step. Enchant nonblack creature Enchanted creature gets +2/+2.

Chandra, Torch of Defiance - (Gatherer) (Scryfall) (EDHREC)

{2}{R}{R} Legendary Planeswalker — Chandra 4 +1: Exile the top card of your library. You may cast that card. If you don't, Chandra, Torch of Defiance deals 2 damage to each opponent. +1: Add {R}{R}. −3: Chandra, Torch of Defiance deals 4 damage to target creature. −7: You get an emblem with "Whenever you cast a spell, this emblem deals 5 damage to any target."

[Alex-Vasile]

This sounds similar to the issue in #8584. See my current preliminary work on it in #9268.