bpo-39573: Finish converting to new Py_IS_TYPE() macro (GH-18601)

diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index d114bd6..92374cc 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -237,7 +237,7 @@
 #if PyTuple_MAXSAVESIZE > 0
         if (len < PyTuple_MAXSAVESIZE &&
             numfree[len] < PyTuple_MAXFREELIST &&
-            Py_TYPE(op) == &PyTuple_Type)
+            Py_IS_TYPE(op, &PyTuple_Type))
         {
             op->ob_item[0] = (PyObject *) free_list[len];
             numfree[len]++;