Allow making both a wrapper and a bridge for a class

[Zverik]

I often encounter this when bridging abstract classes, which are both widely used (and make sense to be wrapped), and are meant to be subclassed. The common example of this is StatelessWidget in flutter_eval, which is also wrapped twice.

[ethanblake4]

I am pretty sure that the compiler does not actually support using both a bridge and a wrapper in the same program, so generating both of them won't do much. I could be wrong though, did you happen to test it?

[Zverik]

Right, I was not paying attention to StatelessWidget, that it doesn't declare anything and is used just to wrap classes. I have rewrote the method to add a light-weight wrapper then. Please take another look.

Also, I did test adding a same declaration twice to a compiler, and weirdly it worked :)

[ethanblake4]

Ah, I suppose this is a reasonable thing to add. So the wrapper is not being directly used by the compiler but is just for end-user usage. Yeah, in that case the compiler won't even be directly aware of it, but because it shares the same type spec as the bridge version it shouldn't complain...