vm-under-test: Permanently disable swap space

Disabling swap space since it will introduce potential latency.
In order to permanently disable [0], this commit is:
- using the swapoff command.
- commenting the swap entries on /etc/fstab.
- masking the swap service with systemctl

[0] https://askubuntu.com/questions/440326/how-can-i-turn-off-swap-permanently/984777#984777

Signed-off-by: Ram Lavi <ralavi@redhat.com>

vms/vm-under-test/scripts/first-boot

@@ -26,4 +26,8 @@ echo isolated_cores=1-2 >> /etc/tuned/realtime-virtual-guest-variables.conf
 echo isolate_managed_irq=Y >> /etc/tuned/realtime-virtual-guest-variables.conf
 tuned-adm profile realtime-virtual-guest
 
+swapoff -a
+sed -i '/swap/s/^/#/' /etc/fstab
+systemctl mask "$(systemctl --type swap | grep '.swap' | awk '{print $1}')"
+
 reboot