Fix saving hexagonal maps to image

The calculated image size was never exactly matched by a renderer update,
resulting in the image never being saved. The stall temporary renderer was then
blocking map updates. Only require the renderer update to be larger than the
calculated size, which will always happen since we trigger a full update.

In addition, remove wrong size heuristics for iso-hex tilesets: they behave
just like normal isometric tilesets.

Closes #1642.

(cherry picked from commit 5b04e82)

client/menu.cpp

@@ -2795,10 +2795,7 @@ void mr_menu::save_image()
   // The size of the image we want to render
   QSize full_size((wld.map.xsize + 2) * tileset_tile_width(tileset),
                   (wld.map.ysize + 2) * tileset_tile_height(tileset));
-  if (tileset_hex_width(tileset) > 0) {
-    full_size.rheight() *= 11;
-    full_size.rheight() /= 20;
-  } else if (tileset_is_isometric(tileset)) {
+  if (tileset_is_isometric(tileset)) {
     full_size.rheight() /= 2;
   }
 
@@ -2810,7 +2807,7 @@ void mr_menu::save_image()
       renderer, &freeciv::renderer::repaint_needed,
       [=](const QRegion &where) {
         // Maybe some other update sneaked in -- make sure to ignore it
-        if (where.boundingRect().size() == full_size) {
+        if (where.boundingRect().contains(QRect(QPoint(), full_size))) {
           // File path
           QString img_name =
               QStringLiteral("Freeciv21-Turn%1").arg(game.info.turn);