lisa.tests.scheduler.eas_behavior: Align get_big_duty_cycle() parameter with unscaled_utilization()
lisa.tests.scheduler.eas_behavior: Align get_big_duty_cycle() parameter with unscaled_utilization()

* Use utilization_pct instead of load
* Use utilization_pct=None as a default and marker value instead of negative
  values.

ARM-software/lisa,credp/lisa,credp/lisa,ARM-software/lisa,credp/lisa,ARM-software/lisa,credp/lisa,ARM-software/lisa