test-string-input-visitor: Add range overflow tests

Let's make sure that the range handling code can properly deal with
ranges that end at the biggest possible number.

Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20181121164421.20780-10-david@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>