Revert "pythongh-128691: Use deferred reference counting on _thread._local (python#128693)"

This reverts commit c141748.

Author: hugovk

Modules/_threadmodule.c

@@ -1414,10 +1414,6 @@ local_new(PyTypeObject *type, PyObject *args, PyObject *kw)
         return NULL;
     }
 
-    // gh-128691: Use deferred reference counting for thread-locals to avoid
-    // contention on the shared object.
-    _PyObject_SetDeferredRefcount((PyObject *)self);
-
     self->args = Py_XNewRef(args);
     self->kw = Py_XNewRef(kw);