qemu.tests: Add a qemu subtest script multi_vms_nics.py

Mainly test steps:
1. Check if the NIC number in guest matches that specified in config file.
2. Get the ip-mac pair in guest.
3. Gather the ping info by tcpdump.
4. Check if the ip-mac info matches in the tcpdump output.
5. Check if the ping count matches the given number.

Signed-off-by: Bear <byang@redhat.com>
Signed-off-by: Ken Cao <kcao@redhat.com>
Signed-off-by: Yolkfull Chow <yzhou@redhat.com>
Signed-off-by: Feng Yang <fyang@redhat.com>
KVM-test: Multi nic test case improve
Signed-off-by: Yiqiao Pu <ypu@redhat.com>
KVM Test: multi_nics: Fix argument order for scp_between_remotes
Signed-off-by: Qingtang Zhou <qzhou@redhat.com>
KVM Test: Refactor multi_nics.py test script
Rename multi_nics.py to multi_vms_nics.py
Support multi vms and multi nics.
Signed-off-by: Feng Yang <fyang@redhat.com>
qemu: Fix syntax error in multi_nics.py
Signed-off-by: Feng Yang <fyang@redhat.com>