swift234

ClangImporter: Don't attempt to bridge __unsafe_unretained NSString * fields in structs.

We certainly can't import them as stored properties, and it's too late to try to bridge them as computed property, so restore the old behavior of importing them as unbridged object types. The types still come in as strong managed reference types, which is still wrong, but seems to be right enough for Khan Academy and potentially other existing apps for now, and I don't want to introduce additional source-breaking changes and instability this late in the game. Fixes rdar://problem/19789023, leaving rdar://problem/19790608 to be done when we can afford more churn.

Swift SVN r25158