twister: cleanup how we capture results of handlers

we use reason for a failure to indicate state and then set the status
later and reason for the failure, in case of the failure is taken from
the handler status. Clean this up by setting status and reason coming
from the handler very early, so we do not have to go through replacing
meaning later.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>