ResolveAll returns the first class registered twice

I reported this as an issue in [Nancy#1657](https://github.com/NancyFx/Nancy/issues/1657) but I think it's a bug in TinyIoC. The Nancy issue has a repro and I put together a failing test that I think is correct. I haven't tried to fix this though because I'm not familiar enough with TinyIoC to know if this is really a bug or intended functionality.