'not' on Windows tries and fails to convert the argument to UTF-16 and back for
some reason:
Error: Unable to convert command-line to UTF-16
Let's try replacing it with !.
(There was no obvious way to do these with FileCheck)
llvm-svn: 195907
1) Use %clang_cc1 instead of the driver
2) Validate that the input contains a BOM
3) Validate that the BOM has been stripped from the output
llvm-svn: 195886