- it is required to be able to autoimport extensions from objects,
not only from the top level
- use `substituteExtensionIfCallable` to handle generics for extension methods
- move finding expression receivers to the separate method, add `Receivers` value class to hold found receivers
- change `CallableDescriptor.isValidByReceiversFor` to return false
if explicit receiver is not required for the descriptor
- ^KT-34000 Fixed
Roman Golyshev