Looks like the problem occurs when the extent specified by bestView crosses 180 degrees longitude. You end up with an extent where xmin > xmax. This obviously doesn't work...Simple workaround would be to check for this and flip the sign on xmin if xmin > xmax:
var bv = geocodeResults[0].bestView;
if ( bv.xmin > bv.xmax ) {
geocodeResults[0].bestView.xmin = bv.xmin * -1;
}
map.setExtent(esri.geometry.geographicToWebMercator(geocodeResults[0].bestView));