[ObjectiveC] Invalid bindings generated for AVFAudio framework

# Context

I was playing around with the objective_c example and using a glob for the entrypoint: `AVFAudio.framework/**.h` instead of `AVFAudio.framework/Headers/AVAudioPlayer.h`. I noticed a few issues with the generated bindings.

# Issues

There are 2 issues that I noticed with the bindings (#578 and dart-lang/native#452), and 1 more general issue with some of the interfaces being included:

## Objective C interfaces are included, even if not referenced from an included interface with `exclude-all-by-default: true`

I'm not sure why the `AVAudioNode` is included, except perhaps that there's a section in `AVAudioPlayer.h`:
```c++
#if __has_include()
#import
#endif
```
And, since I am using a glob pattern for the entry points, `AVAudioSession.h` was included and **it** indirectly references `AVAudioNode`. I think the way we're filtering out declarations may need to be more granular. This also could reduce the size of generated bindings, in general.