tests: Load vhost modules explicitly while Kata installing

The default network backend of runtime-rs with Dragonball is vhost-net
after kata-containers#8609 merged. The tests might be failed if vhost modules are not
loaded.

Fixes: kata-containers#8717

Signed-off-by: Xuewei Niu <niuxuewei.nxw@antgroup.com>

tests/common.bash

@@ -393,6 +393,7 @@ function install_kata() {
 		restart_crio_service
 	fi
 
+	load_vhost_mods
 }
 
 # creates a new kata configuration.toml hard link that
@@ -714,3 +715,10 @@ function get_test_version(){
 
         get_dep_from_yaml_db "${db}" "${dependency}"
 }
+
+# Load vhost, vhost_net, vhost_vsock modules.
+function load_vhost_mods() {
+	modprobe vhost
+	modprobe vhost_net
+	modprobe vhost_vsock
+}