Add director_nested_class testcase

Java nested director class test for fix in e7db081d5e

Examples/test-suite/director_nested_class.i

@@ -0,0 +1,16 @@
+%module(directors="1") director_nested_class
+
+
+%feature("director") DirectorOuter::DirectorInner;
+
+%inline %{
+struct DirectorOuter {
+  struct DirectorInner {
+    virtual ~DirectorInner() {}
+    virtual int vmethod(int input) const = 0;
+  };
+  static int callMethod(const DirectorInner &di, int value) {
+    return di.vmethod(value);
+  } 
+};
+%}