Added clear cache methods to clear the internal type lookup cache for ref leak test runs.
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 4939f54..f5465c5 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -377,6 +377,9 @@
 	Py_XDECREF(warnings_module);
 	warnings_module = NULL;
 
+	/* Clear type lookup cache */
+	PyType_ClearCache();
+
 	/* Collect garbage.  This may call finalizers; it's nice to call these
 	 * before all modules are destroyed.
 	 * XXX If a __del__ or weakref callback is triggered here, and tries to