Pathlib.iterdir semantics change dramatically under Python 3.13

Bug report

Bug description:

This code behaves very differently on Python 3.13 than 3.12:

(p for p in pathlib.Path('does-not-exist').iterdir())

 🐚 py -3.12 -c "import pathlib; (p for p in pathlib.Path('does-not-exist').iterdir())"
 🐚 py -3.13 -c "import pathlib; (p for p in pathlib.Path('does-not-exist').iterdir())"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    import pathlib; (p for p in pathlib.Path('does-not-exist').iterdir())
                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/homebrew/Cellar/python@3.13/3.13.1/Frameworks/Python.framework/Versions/3.13/lib/python3.13/pathlib/_local.py", line 575, in iterdir
    with os.scandir(root_dir) as scandir_it:
         ~~~~~~~~~~^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 'does-not-exist'

In Python 3.12, the generator expression was evaluated lazily, not invoking path.iterdir() until the generator was consumed. On 3.13, at least a portion of the generator is evaluated, triggering the exception when the dir does not exist.

I discovered this issue in https://github.com/jaraco/jaraco.develop/issues/26.

I looked at What's New for Python 3.13, and there's only one mention of generator expressions regarding mutation of locals in generator expressions, which doesn't seem to be relevant here.

That change mentions https://github.com/python/cpython/issues/74929, so maybe that change is also implicated in the change in execution order.

CPython versions tested on:

3.13

Operating systems tested on:

macOS

Python 3.12 および 3.13 でジェネレーター式の動作を再現し、その後 pathlib/_local.py の 575 行目付近と、issue 74929 で議論されているジェネレーター式のセマンティクスを調査してください。変更された評価順序が意図的なものか、それともリグレッションなのかを判断し、FileNotFoundError が発生する想定時点を示す、焦点を絞ったリグレッションテストを追加してください。