bpo-39573: Use Py_TYPE() macro in Modules directory (GH-18393)

Replace direct access to PyObject.ob_type with Py_TYPE().
diff --git a/Modules/parsermodule.c b/Modules/parsermodule.c
index ef63ca9..f00329b 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -256,7 +256,7 @@
 
 
 /* PyST_Type isn't subclassable, so just check ob_type */
-#define PyST_Object_Check(v) ((v)->ob_type == &PyST_Type)
+#define PyST_Object_Check(v) (Py_TYPE(v) == &PyST_Type)
 
 static int
 parser_compare_nodes(node *left, node *right)