Use a deterministic order for files when calculating psmdcp hash

NuGet Product(s) Involved

dotnet.exe

The Elevator Pitch

With reproducible builds, software can become more trustworthy, transparent and secure. It becomes easier to verify that binaries have not been tampered with it, and easier to identify some types of security attacks.

As part of that, it would be great if nupkgs were fully reproducible.

One current area of non-reproducibility, missed in https://github.com/NuGet/Home/issues/14448, is the order of files used to generate the psmdcp hash in PackageBuilder .

NuGet.Client's PackageBuilder.CalcPsmdcpName relies on the order the files defined in the manifest. The order is non-deterministic when file globs are used (example). We should make this order well-defined.

Additional Context and Details

Relates to https://github.com/dotnet/source-build/issues/4963