Fail reproducibility checks on engine errors or missing node output
Enable pipefail so Expect failures and grep's no-match status reach the existing error trap instead of being hidden by a successful final awk.
Only extract node counts from info lines. Expect echoes go nodes commands, which otherwise let a run without node reports pass even with pipefail.
closes https://github.com/official-stockfish/Stockfish/pull/7151
No functional change
Co-authored-by: Naman Jain <113119796+jainaman-umich@users.noreply.github.com>