futhark autotune: --timeout doesn't work

[athas]

Timeouts became broken when we moved to using a server-mode process. Worse, the remaining half-baked timeout support actually corrupts the "state machine" used, so you get weird crashes as Futhark gets confused about which commands receive which responses.

The right solution is that a timeout should cause the entire process to be terminated and started up anew. This will unfortunately require clever programming to avoid making the control flow completely incomprehensible (it'll basically have to be an event-driven state machine).