This adjusts the tests for the difference between line endings on
different platforms. Windows uses CRLF while most Unicies use LF. This
was exposed during the update to the new LLVM snapshot.
The code goes into its own sub-tree under 'tools' but tests go under 'test',
so that running 'check-swift' will also run all the SourceKit tests.
SourceKit is disabled on non-darwin platforms.
Richard Wei
Doug Gregor
Arnold Schwaighofer
Rintaro Ishizaki
Saleem Abdulrasool
Argyrios Kyrtzidis