Single-file apps are not re-extracted if folder in temp is empty in .NET Core 3

[jespergustinmsft]

Windows periodically deletes files in %temp% but keep the folder of the extracted single-file app. And it seems that the files are not re-extracted if the folder already exists (and empty).

This seems to be fixed in .NET 5(?) as I have not been able to reproduce it there.

How to reproduce:

1. Publish a single-file app (MyApp.exe in this case)
2. Run it (to produce a temporary folder, e.g. C:\Users\user\AppData\Local\Temp.net\MyApp\vslj0aom.wch)
3. Delete the contents of vslj0aom.wch, but keep the folder, to mimic the behavior of the periodical Windows clean-up
4. Try to start MyApp.exe again

RESULT: Application won't start, because files are not re-extracted to %temp%.net\MyApp if vslj0aom.wch exists and empty.
EXPECTED RESULT: Application starts regardless of the state of the temporary directory (with files).

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.