Worst Fears (and possibly similar effects): caster still controls the target if the caster lost the game or otherwise left

Just happened in a game. An opponent cast Worst Fears on me. They lost the game before my next turn, and left. It still gave them control of my turn. Upon timing out after 300 seconds, they *still* had control over my turn and the game could not be completed.

Start by reproducing Worst Fears when its caster loses the game or leaves before the target's next turn, then trace the turn-control handling in the game engine. Done means the departed caster no longer controls the target's turn and the game completes normally instead of timing out.

Written by the indexing model from the issue text.