Why does filtering by a Owner Id and Owner Type fail in unit tests?
Is there an alternative way of doing this query with just one query, and not two, just for the sake of unit tests?
As a trusty and time tested pattern for getting around SOQL Limitations, I would use a formula here:
OR(OwnerId = $User.Id, Owner.Type = "Queue")
And then you can just change your filter to:
WHERE IsOwnedByMeOrQueue__c = true