Possibly superfluous backslash in proc_open() escaping on Windows

### Description

The following code:

```php
<?php
proc_open(["test.bat", "\"&notepad.exe"], …);
```

passes `"test.bat" ^"\^"^&notepad.exe^"` to `CreateProcess()`. The backslash appears to be superfluous.


### PHP Version

PHP 8.2

### Operating System

Windows