render: Clip bresenham lines against a real viewport thing.

You can't just use renderer->view->viewport, because it might be (0,0), -1x-1.

I _think_ this is more right?

Fixes #8609.

src/render/SDL_render.c

@@ -2755,11 +2755,13 @@ static int RenderLineBresenham(SDL_Renderer *renderer, int x1, int y1, int x2, i
     int retval;
     SDL_bool isstack;
     SDL_FPoint *points;
+    SDL_Rect viewport;
 
     /* the backend might clip this further to the clipping rect, but we
        just want a basic safety against generating millions of points for
        massive lines. */
-    if (!SDL_GetRectAndLineIntersection(&renderer->view->viewport, &x1, &y1, &x2, &y2)) {
+    GetRenderViewportInPixels(renderer, &viewport);
+    if (!SDL_GetRectAndLineIntersection(&viewport, &x1, &y1, &x2, &y2)) {
         return 0;
     }