bpo-45315: PyType_FromSpec: Copy spec->name and have the type own the memory for its name (GH-29103)

Include/cpython/object.h

@@ -290,6 +290,7 @@ typedef struct _heaptypeobject {
     PyObject *ht_name, *ht_slots, *ht_qualname;
     struct _dictkeysobject *ht_cached_keys;
     PyObject *ht_module;
+    char *_ht_tpname;  // Storage for "tp_name"; see PyType_FromModuleAndSpec
     /* here are optional user slots, followed by the members. */
 } PyHeapTypeObject;