Remove setCenter() from map.dimensions()

This was triggering a weird redraw which made the map slow and look wrong
The map will redraw again in a few milleseconds anyway.

This means that the the map will not stay on the center, but rather the
top-left corner, which kind of feels better anyway, as it doesn't move things
around as much.

modules/renderer/map.js

@@ -662,13 +662,11 @@ export function rendererMap(context) {
 
     map.dimensions = function(_) {
         if (!arguments.length) return dimensions;
-        var center = map.center();
         dimensions = _;
         drawLayers.dimensions(dimensions);
         context.background().dimensions(dimensions);
         projection.clipExtent([[0, 0], dimensions]);
         mouse = utilFastMouse(supersurface.node());
-        setCenter(center);
 
         scheduleRedraw();
         return map;