Add invalid deref tests.

test/NullDeref/Iterator.C

@@ -0,0 +1,24 @@
+//------------------------------------------------------------------------------
+// CLING - the C++ LLVM-based InterpreterG :)
+//
+// This file is dual-licensed: you can choose to license it under the University
+// of Illinois Open Source License or the GNU Lesser General Public License. See
+// LICENSE.TXT for details.
+//------------------------------------------------------------------------------
+
+// RUN: cat %s | %cling -Xclang -verify
+// This test verifies that we do not produce a warning when an iterator is derefed.
+
+#include <vector>
+
+class MyClass {
+public:
+  MyClass() {}
+};
+
+std::vector<MyClass*> vect(3);
+for (auto it = vect.begin(), end = vect.end(); it != end; ++it)
+	printf("%s\n", *it);
+
+.q
+