Fix the Unix CI by adding an explicit destructor

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

tests/VTables/VTables.cpp

@@ -4,6 +4,10 @@ Foo::Foo()
 {
 }
 
+Foo::~Foo()
+{
+}
+
 int Foo::vfoo()
 {
     return 5;

tests/VTables/VTables.h

@@ -10,6 +10,7 @@ public:
     };
 
     Foo();
+    ~Foo();
     virtual int vfoo();
     virtual int vbar();