Major Description
Currently thermos process's teardown from the end of `ACTIVE` stage to the end of `FINALIZING` must happen within 'finalization_wait' seconds. If it does not finish during that time, all remaining processes are sent SIGKILLs. That normally happens if a process doesn't respond to SIGTERM signal. finalization_wait timeout is based on THERMOS_PREEMPTION_WAIT timeout in thermos task runner that is hardcoded to 1 minute. It seems to be useful to make it configurable via thermos executor flags.
