cocoa: Check the resizable flag along with zoomed status when resizing

isZoomed always returns true if the window is not resizable, so the resizable flag needs to be checked as well.

src/video/cocoa/SDL_cocoawindow.m

@@ -2209,7 +2209,8 @@ void Cocoa_SetWindowSize(SDL_VideoDevice *_this, SDL_Window *window)
             Cocoa_SyncWindow(_this, window);
         }
 
-        if (!Cocoa_IsZoomed(window)) {
+        /* isZoomed always returns true if the window is not resizable */
+        if (!Cocoa_IsZoomed(window) || !(window->flags & SDL_WINDOW_RESIZABLE)) {
             if (!(window->flags & SDL_WINDOW_FULLSCREEN)) {
                 [nswindow setFrame:[nswindow frameRectForContentRect:rect] display:YES];
                 ScheduleContextUpdates(windata);