Make `os.scandir` retry on system calls failing with EINTR

Bug report

Bug description:

In a long-running script, I hit:

[…]
  File "/Users/gsnedders/ct.py", line 104, in worker
    with os.scandir(path) as it:
         ~~~~~~~~~~^^^^^^
InterruptedError: [Errno 4] Interrupted system call: '/Users/gsnedders/Library/Containers/com.apple.ScreenTimeWidgetApplication.ScreenTimeWidgetExtension/Data/Library/Application Scripts'

No repro case is provided, because that would require making syscalls fail with EINTR reliably somehow.

PEP 475 (Retry system calls failing with EINTR) implies to me that os.scandir should be retrying, rather than just failing here.

It does appear that os.scandir doesn't always retry, looking at the source:

https://github.com/python/cpython/blob/ae3064608935367c860182dc1b364631082ecdff/Modules/posixmodule.c#L16489

The iterator itself also seems to not retry:

https://github.com/python/cpython/blob/ae3064608935367c860182dc1b364631082ecdff/Modules/posixmodule.c#L16290

CPython versions tested on:

3.13

Operating systems tested on:

macOS

Lee PEP 475 y la implementación enlazada de os.scandir en Modules/posixmodule.c, incluido el código del iterador en las líneas referenciadas. Comprueba cómo se gestionan las llamadas al sistema que devuelven EINTR y verifica que os.scandir reintenta en lugar de lanzar InterruptedError. Se considerará completado cuando tanto la llamada inicial como el comportamiento del iterador coincidan con la política de reintentos prevista.