fix deadlock in type_set_abstractmethods

Author: kumaraditya303

Objects/typeobject.c

@@ -1706,14 +1706,17 @@ type_set_abstractmethods(PyObject *tp, PyObject *value, void *Py_UNUSED(closure)
         return -1;
     }
 
+    pinned_mutexes_t pinned;
     BEGIN_TYPE_LOCK();
     _PyType_Modified_Unlocked(type);
+    type_lock_prevent_release(&pinned);
     types_stop_world();
     if (abstract)
         type_add_flags(type, Py_TPFLAGS_IS_ABSTRACT);
     else
         type_clear_flags(type, Py_TPFLAGS_IS_ABSTRACT);
     types_start_world();
+    type_lock_allow_release(&pinned);
     ASSERT_TYPE_LOCK_HELD();
     END_TYPE_LOCK();