tests, arm: Make switcheroo and checkpoint tests functional

Switcheroo and checkpoint tests should generally be considered to be
successful if they run to completion. Remove all reference output
files from the switcheroo and checkopint tests to make them purely
functional.

Change-Id: I70b47853bd662b7a33716d9e0d2154b16077f9dc
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>