tests: add CVM test for dmi_uuid

Add a CVM variant of the DMI UUID test in
integration_cvm.rs. This test creates a confidential
guest using the basic_cvm_guest! macro and invokes the
shared _test_dmi_uuid() wrapper to validate DMI UUID
behavior under CVM.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

cloud-hypervisor/tests/common/tests_wrappers.rs

@@ -2238,4 +2238,4 @@ pub(crate) fn _test_dmi_uuid(guest: &Guest) {
     let output = child.wait_with_output().unwrap();
 
     handle_child_output(r, &output);
-}
+}