lisa.tests.scheduler.load_tracking: Add missing noise check
lisa.tests.scheduler.load_tracking: Add missing noise check

FIX

RqInvariance tests predict rq signals by looking at the test task signal
only. This means it's susceptible to interferences if another task in
the system wakes up.

Add the noisy task check to ensure the trace is free of unwanted
activations.

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