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/bytearrayobject.c b/Objects/bytearrayobject.c
index c9bf11b..a019b49 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -856,7 +856,7 @@
         if (PyErr_ExceptionMatches(PyExc_TypeError)) {
             PyErr_Format(PyExc_TypeError,
                          "cannot convert '%.200s' object to bytearray",
-                         arg->ob_type->tp_name);
+                         Py_TYPE(arg)->tp_name);
         }
         return -1;
     }
@@ -1630,7 +1630,7 @@
         if (PyErr_ExceptionMatches(PyExc_TypeError)) {
             PyErr_Format(PyExc_TypeError,
                          "can't extend bytearray with %.100s",
-                         iterable_of_ints->ob_type->tp_name);
+                         Py_TYPE(iterable_of_ints)->tp_name);
         }
         return NULL;
     }