lisa.tests.scheduler.load_tracking: Add assert to check duty_cycle_pc…

Created by: deggeman

…t > 0

Occasionally the load_tracking invariance tests [load|util]_[correctness|behaviour] fail on rb5 little/medium CPUs on low frequencies. The root cause is wrong rt-app calibration for these CPUs/frequencies. The reason for the rt-app calibration issue is not known at the moment. Add an assert in _get_rtapp_profile() of class InvarianceItemBase to catch the issue earlier.

Signed-off-by: Dietmar Eggemann dietmar.eggemann@arm.com