Add Diagnostic files for Frontend and move a couple errors over.
 - Notably, clang now exits with an error if it can't find a
   file. This flushed out a bug in the CGColorSpace.c test case. :)


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66789 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed