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

[Dan Liew via llvm-commits]

delcypher wrote:

@canova @dvyukov It looks like this PR may have caused a test failure on the macOS bots.

https://green.lab.llvm.org/job/llvm.org/job/clang-stage1-RA/168/testReport/junit/ThreadSanitizer-x86_64/ThreadSanitizer-x86_64/signal_in_futex_wait_cpp/

The `signal_in_futex_wait.cpp` test looks Linux specific but is not prevented from running on other platforms. If this test is meant for Linux only could it be marked to not execute on other platforms?

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