MINOR: Fixed EventRegistrationPurgeTaskTest sometimes failing if it took a long time to run.
MINOR: Fixed EventRegistrationPurgeTaskTest sometimes failing if it took a long time to run.

burnbright/silverstripe-eventmanagement,stephenmcm/silverstripe-eventmanagement,silverstripe-australia/silverstripe-eventmanagement,souldigital/silverstripe-eventmanagement,burnbright/silverstripe-eventmanagement,registripe/registripe-core,souldigital/silverstripe-eventmanagement,stephenmcm/silverstripe-eventmanagement,silverstripe-australia/silverstripe-eventmanagement