`Path("").exists()` always returns True, which is a bug

# Bug report

### Bug description:

```python
from pathlib import Path
print(Path("").exists())

import os
print(os.path.exists(""))
```

For empty string "", pathlib returns True, but os returns False.

Clearly, os is right, because you can't read anything from "".


### CPython versions tested on:

3.10

### Operating systems tested on:

Linux