Add proper explanation for cin.sh.cpp fail. The stdin-is-piped.sh.cpp used to fail with old qemu (4.2.0), but should pass now, as the qemu is updated now to 8.1.3 in CI.
Add proper explanation for cin.sh.cpp fail. The stdin-is-piped.sh.cpp used to fail with old qemu (4.2.0), but should pass now, as the qemu is updated now to 8.1.3 in CI.