The official Pokémon GO page has announced that Armored Mewtwo can be challenged in Tier 5 raids, from July 10th, 1pm PDT to July 31st, 1pm PDT.
While the Japanese trailer explicitly mentions it is a crossover event with the Movie: Mewtwo Strikes Back EVOLUTION, this information was missing from the English trailer, presumably because the movie is out in the West yet.
Presently, there is no official mention of this event being tied to the datamined Shadow Pokémon.
Based on the trailer, it appears Armored Mewtwo can have Ice Beam has it's charged move.
Presently, it is unknown if it'll retain the same stats and same moves as a regular Mewtwo.