...since all imports are private by default, and we rely on "import Cocoa"
bringing in AppKit. (If you say "import AppKit" directly, you get an
immediate call to IRGenImportedModules, so everything works.)
Swift SVN r12617
1) Revert my change to give DeclContext a dump method, it confuses the debugger.
2) Refactor SILGen::requiresObjCPropertyEntryPoints out to
VarDecl::usesObjCGetterAndSetter.
Swift SVN r12526
In order to implement immediate and REPL modes in swift_driver, this functionality
needs to be in a library (instead of directly in the swift executable).
Swift SVN r12519
