Fixed an issue where the C# class name was coming in with `,
AssemblyName` tacked on the end.
Fixed an issue where a class that had an entry in the map didn't have a
`class_ptr` which was causing an NRE.
Fixed a predicate for deciding when to mark the assembly for save.
Note - for an as yet undetermined reason, the linker is not picking up
that I'm marking the assembly for save, which is why the `true` test
cases are commented out.
This fixes issue 16671 https://github.com/xamarin/xamarin-macios/issues/16671
Steve Hawley