gh-159739: Break reference cycles involving property objects

Backport to 3.15 and 3.14.

Author: jelle-openai

Misc/NEWS.d/next/Core_and_Builtins/2026-10-20-00-00-00.gh-issue-159739.848b18.rst

@@ -0,0 +1,2 @@
+Allow the garbage collector to break reference cycles involving property
+accessors or names.

Objects/descrobject.c

@@ -2007,7 +2007,11 @@ static int
 property_clear(PyObject *self)
 {
     propertyobject *pp = (propertyobject *)self;
+    Py_CLEAR(pp->prop_get);
+    Py_CLEAR(pp->prop_set);
+    Py_CLEAR(pp->prop_del);
     Py_CLEAR(pp->prop_doc);
+    Py_CLEAR(pp->prop_name);
     return 0;
 }