sheye: SchedAssert: Add assertDutyCycle
sheye: SchedAssert: Add assertDutyCycle

assertDutyCycle facilitates the assertion of the
duty cycle of the task in a given window of time

Change-Id: I1578e265d0f2a2110e26f1092ca71e33ecae7978
Signed-off-by: Kapileshwar Singh <d373e2b6407ea84be359ce4a11e8631121819e79@arm.com>

sinkap/bart,JaviMerino/bart,ARM-software/bart