Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
the argument types and underlying raw types.
In the long run we'd really want to emit them as DW_TAG_variant_types.
<rdar://problem/14845818> Support enums
Swift SVN r18170
