Rollup merge of #139683 - ChrisDenton:windows-with-native, r=tgross35,joboet

Use `with_native_path` for Windows

Ideally, each platform should use their own native path type internally. This will, for example, allow passing a UTF-16 string directly to `std::fs::File::open` and therefore avoid the need for allocating a new null-terminated wide string. However, doing that for every function and platform all at once makes for a large PR that is way too prone to breaking. So this just does some of the Windows parts.

As with the previous Unix PR (#138832) this is intended to be merely a refactoring so I've avoided anything that may require more substantial changes.

Author: ChrisDenton