bpo-19764: Convert subprocess.Handle to int in handle_list

Author: segevfiner

Lib/subprocess.py

@@ -992,7 +992,7 @@ def _execute_child(self, args, executable, preexec_fn, close_fds,
                 handle_list = attribute_list.setdefault("handle_list", [])
 
                 if use_std_handles:
-                    handle_list += [p2cread, c2pwrite, errwrite]
+                    handle_list += [int(p2cread), int(c2pwrite), int(errwrite)]
 
                 handle_list[:] = self._filter_handle_list(handle_list)