[compiler-rt] [tsan] Add callbacks for futex syscalls and mark them as blocking on tsan (PR #86537)

[Nazım Can Altınova via llvm-commits]

canova wrote:

@delcypher @yln Sorry about the inconvenience! This is indeed a linux only test, moving this test to the Linux subdirectory in #86896.

https://github.com/llvm/llvm-project/pull/86537