clang/test/Headers/opencl-c-header.cl: Add explicit -triple x86_64-unknown to...

clang/test/Headers/opencl-c-header.cl: Add explicit -triple x86_64-unknown to appease *-win32 targets.

  <stdin>:9:25: note: possible intended match here
   %call = tail call i8 @"\01?convert_char_rte@@$$J0YADD@Z"(i8 %x) #2
                          ^

llvm-svn: 273230