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

[Julian Lettner via llvm-commits]

yln wrote:

@canova, as Dan Liew (delcypher) mentioned above, the test added in the PR seems to be specific to Linux:
```
#include <sanitizer/linux_syscall_hooks.h>
```

I think the simplest way to only run this test on Linux is to move it into the `compiler-rt/test/tsan/Linux` subdirectory.  Please do this soon.  Thank you!


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