Fix test_inspect.

Author: serhiy-storchaka

Lib/test/test_inspect/test_inspect.py

@@ -5799,7 +5799,7 @@ def test_operator_module_has_signatures(self):
         self._test_module_has_signatures(operator)
 
     def test_os_module_has_signatures(self):
-        unsupported_signature = {'chmod', 'utime'}
+        unsupported_signature = {'chmod', 'link', 'utime'}
         unsupported_signature |= {name for name in
             ['get_terminal_size', 'posix_spawn', 'posix_spawnp',
              'register_at_fork', 'startfile']