Expand version checks to include more

- [x] Include everything we reference from assemblies in Microsoft.AspNetCore.App i.e. don't skip over System.IO.Pipelines or anything else from dotnet/runtime
- This part is about updating our existing tests of Microsoft.AspNetCore.App.Ref and Microsoft.AspNetCore.App.Runtime.* content
- [ ] Check the versions of the assemblies in all shipping packages
- This part is more complicated because we need to baseline all expected versions from other repos, especially `netstandard2.0` assemblies we reference from dotnet/runtime
- Ignore patch versions of all .NET Framework assemblies and what they reference
- Confirm w/ dotnet/runtime what assembly versions they plan to update while in 6.0 servicing
- No need to open anything from other repos i.e. just check our assemblies and their references