rust-coreutils: cut: local logic error and data integrity issue in output filtering

A logic error in the cut utility of uutils coreutils causes the utility to ignore the -s (only-delimited) flag when using the -z (null-terminated) and -d '' (empty delimiter) options together. The implementation incorrectly routes this specific combination through a specialized newline-delimiter code path that fails to check the record suppression status. Consequently, uutils cut emits the entire record plus a NUL byte instead of suppressing it. This divergence from GNU coreutils behavior creates a data integrity risk for automated pipelines that rely on cut -s to filter out undelimited data.