Fix viewport.fitBounds tests.
Fix viewport.fitBounds tests.

LarissaSmith/openseadragon,avandecreme/openseadragon,msalsbery/openseadragon,rdlester/openseadragon,openseadragon/openseadragon,LarissaSmith/openseadragon,jmnetus/openseadragon,openseadragon/openseadragon,seanich/openseadragon,seanich/openseadragon,rdlester/openseadragon,msalsbery/openseadragon,avandecreme/openseadragon,jmnetus/openseadragon