C#: Add some compound sink examples.

Author: michaelnebel

csharp/ql/test/utils/modelgenerator/dataflow/Sinks.cs

@@ -79,3 +79,16 @@ public void WrapPropPrivateSetResponseWriteFile()
         response.WriteFile(PrivateSetTaintedProp);
     }
 }
+
+public class CompoundSinks
+{
+    public void WrapNewSinkProp(NewSinks ns)
+    {
+        ns.WrapPropResponseWriteFile();
+    }
+
+    public void WrapNewSinkField(NewSinks ns)
+    {
+        ns.WrapFieldResponseWriteFile();
+    }
+}