As far as I can tell, there's nothing Windows-specific about the
test and it passes fine on other platforms.
I found this test when running
rg clang_cl clang/test | rg '%s' | rg -v -- ' -- ' | rg -v not
after 547ee1c81fceaabcb to see if other tests were missing `--`
before `%s` in `%clang_cl` invocations. This was the only one.
Since it used to run only on Windows, it wasn't needed, but as far
as I can tell there's no reason to run it only on Windows.
Differential Revision: https://reviews.llvm.org/D158279
Validate that we're properly generating a single line ending on Windows when
using -frewrite-includes. Otherwise we're breaking split-line macros. The test
fails before 23929af383f27a6ddf23704192a25591481152b3.
See discussion in https://reviews.llvm.org/D96363#2650460 and D99426
Differential Revision: https://reviews.llvm.org/D99973
