swift

9eb42262 - [ParseableInterface] Turn on -enable-parseable-module-interface always (#23356)

[ParseableInterface] Turn on -enable-parseable-module-interface always (#23356) ...and remove the option. This is ~technically~ CLI-breaking because Swift 5 shipped this as a hidden driver option, but it wouldn't have /done/ anything in Swift 5, so I think it's okay to remove. Note that if a parseable interface (.swiftinterface) and a binary interface (.swiftmodule) are both present, the binary one will still be preferred. This just /allows/ parseable interfaces to be used. rdar://problem/36885834 (cherry picked from commit 22f9853b76a33c90a266c1bfc9027383f1eb736a)