swift234

[ClangImporter] Preserve the CFIndex typealias.

NSInteger and NSUInteger are such core Cocoa types that it will be clearly
documented that they're bridged to Int. However, I can easily see someone
trying to use CFIndex and not understanding why it's missing.

At some point we may want a general solution for all the mapped types
("don't use intptr_t directly; use Int"), but for now treat CFIndex
specially.

Swift SVN r14071