Behemoth proximity damage does not work correctly when redirected

[jamespicone]

When Behemoth's end-of-turn proximity damage is redirected, the damage dealt is based on the new target's proximity token count, not the old target's proximity token count. This seems to be because the dynamic damage amount passed into DealDamage doesn't get evaluated until the final DealDamageAction is constructed.

Omnitron's Technological Singularity is a reference point here; it seems to manually implement the target selection logic etc..