virt.tests: add configuration for pxe boot with query cpus tests

Signed-off-by: NXu Tian <xutian@redhat.com>

tests/cfg/pxe.cfg

@@ -3,7 +3,7 @@
     type = pxe
     requires_root = yes
     images = pxe
-    image_name_pxe = pxe-test
+    image_name_pxe = images/pxe-test
     image_size_pxe = 1G
     force_create_image_pxe = yes
     remove_image_pxe = yes
@@ -13,3 +13,10 @@
     restart_vm = yes
     pxe_timeout = 60
     image_verify_bootable = no
+    variants:
+        - @default:
+        - with_query_cpus:
+            type = pxe_query_cpus
+            start_vm = no
+            restart_vm = no
+            kill_vm = yes