Function normalize_migration_statements 

pub fn normalize_migration_statements(
    slots: &[String],
) -> Result<Vec<String>, StatementRunError>

Normalize migration carrier slots by splitting each one and flattening retained statement bytes in order. Delimiters and trimmed outer whitespace are not identity; comments and whitespace retained inside each statement remain byte-significant. A slot-less migration is a valid version-only journal entry; a supplied slot must still contain a statement.