Only set a process's start time when starting the main thread.  There's also no need to protect that and the setting of the AFORK accounting flag with the scheduler lock.
Only set a process's start time when starting the main thread.  There's
also no need to protect that and the setting of the AFORK accounting flag
with the scheduler lock.

ok mikeb@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars