swift234

Remove NSTypedArray and the iboutletcollection hack.

The hack was that __attribute__((iboutletcollection(NSView))) can be
specified on a collection property to provide its value type, and the
ClangImporter library co-opted that as a way to import NSArray properties
as NSTypedArray<NSView> (or whatever), a layout-compatible Swift struct
type that provided a typed (runtime-checked) view of an NSArray. The
implementation of NSTypedArray was never completed, however; none of
our sample code is actually using it; and it turns out to be problematic
for some instances of lazy type checking (because NSTypedArray is defined
in Swift). Remove it; we'll revisit this later.

Swift SVN r8639