Also, if warning about an accessor that comes from a stored property,
point to the property rather than the (implicit, source-location-less)
accessor decl.
Both of these changes are aimed at improving the presentation in Xcode.
rdar://problem/19927828
Swift SVN r25725
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
