bpo-42519: Replace PyObject_MALLOC() with PyObject_Malloc() (GH-23587)

No longer use deprecated aliases to functions:

* Replace PyObject_MALLOC() with PyObject_Malloc()
* Replace PyObject_REALLOC() with PyObject_Realloc()
* Replace PyObject_FREE() with PyObject_Free()
* Replace PyObject_Del() with PyObject_Free()
* Replace PyObject_DEL() with PyObject_Free()
diff --git a/Modules/cjkcodecs/multibytecodec.c b/Modules/cjkcodecs/multibytecodec.c
index 37a80a7..9208b86 100644
--- a/Modules/cjkcodecs/multibytecodec.c
+++ b/Modules/cjkcodecs/multibytecodec.c
@@ -691,7 +691,7 @@ static struct PyMethodDef multibytecodec_methods[] = {
 static void
 multibytecodec_dealloc(MultibyteCodecObject *self)
 {
-    PyObject_Del(self);
+    PyObject_Free(self);
 }
 
 static PyTypeObject MultibyteCodec_Type = {