Validate ANDed expressions match the same SCO

```[file:name = 'foo' AND domain-name:value = 'example.com']``` passes validation but should not. All Comparison Expressions connected by `AND` must match against the same SCO, which by definition means they must be of the same object type (file != domain-name).

It would be legal if they were connected by `OR` instead: ```[file:name = 'foo' OR domain-name:value = 'example.com']```