Remove gratuitous debug assertions

src/ol/renderer/canvas/canvasvectortilelayerrenderer.js

@@ -306,7 +306,6 @@ ol.renderer.canvas.VectorTileLayer.prototype.forEachFeatureAtCoordinate = functi
          * @return {?} Callback result.
          */
         function(feature) {
-          goog.DEBUG && console.assert(feature, 'received a feature');
           var key = ol.getUid(feature).toString();
           if (!(key in features)) {
             features[key] = true;