[Tcl] Add changed file missed recent commit

This should have been in 6f4adde

Author: ojwb

Examples/test-suite/li_std_vector.i

@@ -140,3 +140,13 @@ std::vector<std::string> RevStringVec (const std::vector<std::string> &In)
     return(result);
   }
 %}
+
+// regression test for Tcl typecheck bug with empty list fixed in 4.2.0
+%inline %{
+int sum(const std::vector<int> &v) {
+  return std::accumulate(v.begin(),v.end(),0);
+}
+int sum(int v) {
+  return v;
+}
+%}