Register cleanup_numbered_dir for atexit before the cleanup for locks…

… is registered (pytest-dev#1120)

The cleanup of the numbered directory will now be executed after
the locks of the current process got removed.

src/_pytest/pathlib.py

@@ -263,12 +263,13 @@ def make_numbered_dir_with_cleanup(root, prefix, keep, lock_timeout):
     for i in range(10):
         try:
             p = make_numbered_dir(root, prefix)
+            consider_lock_dead_if_created_before = p.stat().st_mtime - lock_timeout
             lock_path = create_cleanup_lock(p)
+            atexit.register(cleanup_numbered_dir, root, prefix, keep, consider_lock_dead_if_created_before)
             register_cleanup_lock_removal(lock_path)
         except Exception as exc:
             e = exc
         else:
-            consider_lock_dead_if_created_before = p.stat().st_mtime - lock_timeout
             cleanup_numbered_dir(
                 root=root,
                 prefix=prefix,