[core/process] Fix a bug that fd is not closed by {fd}>&-.

Author: akinomyoga

core/process.py

@@ -302,11 +302,12 @@ def _PushCloseFd(self, loc):
 
     elif loc.tag_() == redir_loc_e.Fd:
       fd = cast(redir_loc__Fd, UP_loc).fd
-      self._PushSave(fd)
 
     else:
       raise AssertionError()
 
+    self._PushSave(fd)
+
     return True
 
   def _PushClose(self, fd):