fix Bean#getBeanClass() definition

currently Bean#getBeanClass() is defined to return the class of the bean it produces but has one important exception: in case of a producer method or field it must return the class of the owner bean of this method or field.

Imo this only causes troubles and doesn't add any benefit.

• At the time when 'using' the Bean (create and destroy) we always ONLY need the type which is to be created.
• At the time we create interceptors we ONLY need the type which is to be created;
• At the time we create the normalscoping proxies we ONLY need the type which is to be created;

In fact the only time we need the ownerBean is when scanning the methods and fields in it. And for creating we really need the owner-Bean and not it's bean-class!

In OWB we worked around this by having our own method getReturnType() which consistently returns the type which gets created.