fileURLToPath returns forward slashes on Windows

* **Version**: v11.6.0
* **Platform**: Win64
* **Subsystem**: url

`url.fileURLToPath` results in a path containing forward slashes instead of backslashes on Windows.

```js
url.fileURLToPath('file:///C:/Users/zenparsing/Code');
// 'C:/Users/zenparsing/Code'
```
