swift234

Move the lit tests over to the new swift/swiftc interfaces

Most of the tests just got moved to swiftc, but some of them were
duplicated to apply to both swiftc and swift. A handful still use the
existing 'swift' because they are for the existing '-i' syntax.

Note: this means config.swift_driver now uses the staging symlink
'swifti'. The only thing preventing us from dropping the 'i' and getting
rid of the old interface is that Xcode hasn't moved to swiftc yet
<rdar://problem/17769327>.

Swift SVN r20467