Since the llvm::sys::fs::map_file_pages() support function it relies on
is not yet implemented on Windows, the unit tests for FileOutputBuffer
are currently conditionalized to run only on unix.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161099 91177308-0d34-0410-b5e6-96231b3b80d8