Add negative tests that fail to match a predicate

negative corpus just assumes that there should be no match at all. We basically want the inverse of `example`.

Start by locating the negative corpus and the existing `example` test helper in the Duckling repository. Confirm how negative cases currently assert that no match exists, then make the requested behavior complete when a negative case can assert that input fails to match a specified predicate.

Written by the indexing model from the issue text.