[CSSimplify] Fix handling of holes by OptionalObject constraint

[xedin]

When "optional type" is a hole the simplification logic has to simplify "object type" and mark all of its unresolved components are potential holes, otherwise hole propagation won't work since sometimes there is no other contextual information for such types but "optional type".

Resolves: rdar://117871338

[xedin]

@swift-ci please test

[xedin]

Oh, I didn't have revert locally 🤦