bpo-39573: Use Py_TYPE() macro in Objects directory (GH-18392)

Replace direct access to PyObject.ob_type with Py_TYPE().
diff --git a/Objects/call.c b/Objects/call.c
index 0f8cb5a..d1d50b6 100644
--- a/Objects/call.c
+++ b/Objects/call.c
@@ -263,11 +263,11 @@
         return PyVectorcall_Call(callable, args, kwargs);
     }
     else {
-        call = callable->ob_type->tp_call;
+        call = Py_TYPE(callable)->tp_call;
         if (call == NULL) {
             _PyErr_Format(tstate, PyExc_TypeError,
                           "'%.200s' object is not callable",
-                          callable->ob_type->tp_name);
+                          Py_TYPE(callable)->tp_name);
             return NULL;
         }