C++: add a test for self-valued iterators

Author: rdmarsh2

cpp/ql/test/library-tests/dataflow/dataflow-tests/self-Iterator.cpp

@@ -0,0 +1,21 @@
+#include "../../../include/iterator.h"
+int source();
+
+template<typename T>
+void sink(T);
+
+template<> struct std::iterator_traits<unsigned long>
+{   // get traits from integer type
+    typedef std::input_iterator_tag iterator_category;
+    typedef unsigned long value_type;
+    typedef unsigned long difference_type;
+    typedef unsigned long distance_type;
+    typedef unsigned long * pointer;
+    typedef unsigned long& reference;
+};
+
+
+int test() {
+    unsigned long x = source();
+    sink(x); // $ ast MISSING: ir
+}