[clang] [Clang] Warn when `std::atomic_thread_fence` is used with `fsanitize=thread` (PR #166542)

[Benjamin Stott via cfe-commits]

BStott6 wrote:

Thanks for the feedback, I have implemented your suggestions
In upgrading the test I found I had made a mistake in how I was handling the calling function being in the ignorelist and also had forgot to handle the no-sanitize attributes, I have implemented this and made sure the test checks for it

https://github.com/llvm/llvm-project/pull/166542