[Checkers] more constructors

[Mahmood Ali]

Hi Telmo,

Actually, .subsitute isn't you would want for resolving polymorphic  
qualifiers anyway.  .substitute substitute _annotated types_ with  
other ones, and not annotations.

You should use SimpleAnnotatedTypeScanner by overriding  
SimpleAnnotatedTypeScanner.defaultAction() instead.

> Can one of you add a test couple to the framework expliciting why  
> this happens, so I can keep working on it?
I'm sorry, I didn't understand 'test couple'.  You can send a patch  
and I will examine it.

- Mahmood