This is mostly just a renaming of _SwiftNativeNSArray, except that we
want to add another NSArray subclass for verbatim-bridged elements, so
we want a common base class. _SwiftNativeNSArray is the name of that
new base class, to parallel the other _SwiftNativeNSXXX classes.
Swift SVN r22913
We're going to replace StdlibUnittest's use of ContiguousArray with
_UnitTestArray so that we can work on (and potentially break)
_ContiguousArray and still get useful test results. When refactoring is
complete, we can optionally replace StdlibUnittest's use of
_UnitTestArray with ContiguousArray, or move the decoupled component
into the StdlibUnittest module.
Swift SVN r22874
