[vala/0.52] tests: Extend "access virtual signal of interface" test to increase coverage

[Rico Tzschichholz <ricotz src gnome org>]

commit 7a9986b54f0c6e657be79deb63e750ee15fe0a77
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Oct 18 12:23:21 2021 +0200

    tests: Extend "access virtual signal of interface" test to increase coverage

 tests/objects/bug642809.vala | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/tests/objects/bug642809.vala b/tests/objects/bug642809.vala
index 91ba53e48..ca248875f 100644
--- a/tests/objects/bug642809.vala
+++ b/tests/objects/bug642809.vala
@@ -5,7 +5,13 @@ interface Foo : Object {
 class Bar : Object, Foo {
 }
 
+class Manam : Object, Foo {
+       public override void virtual_signal () { }
+}
+
 void main () {
        var bar = new Bar ();
        bar.virtual_signal ();
+       var manam = new Manam ();
+       manam.virtual_signal ();
 }