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/unicodeobject.c b/Objects/unicodeobject.c
index fa48ee1..fd08ddb 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -8401,7 +8401,7 @@
         /* wrong return value */
         PyErr_Format(PyExc_TypeError,
                      "character mapping must return integer, bytes or None, not %.400s",
-                     x->ob_type->tp_name);
+                     Py_TYPE(x)->tp_name);
         Py_DECREF(x);
         return NULL;
     }
@@ -11082,8 +11082,8 @@
     }
     PyErr_Format(PyExc_TypeError,
                  "Can't compare %.100s and %.100s",
-                 left->ob_type->tp_name,
-                 right->ob_type->tp_name);
+                 Py_TYPE(left)->tp_name,
+                 Py_TYPE(right)->tp_name);
     return -1;
 }
 
@@ -11353,7 +11353,7 @@
     if (!PyUnicode_Check(right)) {
         PyErr_Format(PyExc_TypeError,
                      "can only concatenate str (not \"%.200s\") to str",
-                     right->ob_type->tp_name);
+                     Py_TYPE(right)->tp_name);
         return NULL;
     }
     if (PyUnicode_READY(right) < 0)