[Bug] Conflict of claws + deathtouch

If a [[Conflict of Claws]] is used on a deathtouch creature, it should discover X - 1 where X is the power. But using it on a 2 power creature, it did 2 damage to the target, and didn't discover (though the creature was destroyed). So the excess damage is probably not calculated properly.

Start by reproducing the interaction between Conflict of Claws and a deathtouch creature with 2 power, then locate the Java implementation and its related tests. Confirm that excess damage is calculated as power minus one and that discovery occurs when appropriate; add or update coverage for this case.

Written by the indexing model from the issue text.