Fix WebGLTile browser tests
Fix WebGLTile browser tests

The loader has to return a TypedArray, not ImageData

ahocevar/openlayers,openlayers/openlayers,bjornharrtell/ol3,openlayers/openlayers,stweil/openlayers,bjornharrtell/ol3,stweil/openlayers,stweil/openlayers,bjornharrtell/ol3,oterral/ol3,oterral/ol3,ahocevar/openlayers,ahocevar/openlayers,oterral/ol3,openlayers/openlayers