Removed invalid code from file test_snapshot_gc.py
CLOUDSTACK-7180: Tagging test case with product bug ID
CLOUDSTACK-7183: Fixing cleanup issue in tsest_escalations_instances.py
Skipping test instead of raising exception in case enough zones are not present for it to run on
Code rector - using library functions instead of repetative code
Removing basic tag from few test cases which should not be run on basic zone
CLOUDSTACK-7181: Skip tests on KVM - changing service offering when VM is in running state - not supported on KVM
Fixing resize volume test case
Changing 'raise exception' to 'skip test' in case not enough hosts available
Fixing vGPU script