Feature: CIB: treat misconfigured date expression as not passing

Previously:

• A date expression missing id would be evaluated anyway;
• A date expression using "in_range" with an invalid start or end would have that part ignored but would otherwise continue to be evaluated;
• A date expression using "in_range" without either a start or end would warn and return "undetermined";
• A date expression using "gt" with a missing or invalid start, or using "lt" with a missing or invalid end, would warn and return "undetermined";
• A date expression using "date_spec" with no date_spec child would return a fail result;
• A date expression with an invalid operation would return a fail result.

Now, these are treated as configuration errors, and the date expression fails.