Refactor existing QoS min bw tests

As a preparation to test QoS minimum bandwidth and minimum packet rate
together this patch refactors the existing MinBwAllocationPlacementTest
test class to allow generalization.

blueprint: qos-minimum-guaranteed-packet-rate

Change-Id: Ie589e114d08cc8bb5a524d6b242f1b29fda43983
1 file changed