Drop `allow_overflow` option in `TimeHelper.duration_in_numbers`

In https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21767, we introduced allow_overflow option for TimeHelper.duration_in_numbers method. This is for avoiding to affect other users of duration_in_numbers such as duration_in_numbers(job.duration), but ideally we should fixe all duration formats, as the old seems broken.

  def duration_in_numbers(duration_in_seconds, allow_overflow = false)
    if allow_overflow
      seconds = duration_in_seconds % 1.minute
      minutes = (duration_in_seconds / 1.minute) % (1.hour / 1.minute)
      hours = duration_in_seconds / 1.hour

      "%02d:%02d:%02d" % [hours, minutes, seconds]
    else
      time_format = duration_in_seconds < 1.hour ? "%M:%S" : "%H:%M:%S"

      Time.at(duration_in_seconds).utc.strftime(time_format)
    end
  end