render: Remove the logical presentation render target.

Now we render directly to the window, scaling as appropriate. This fixes some
concerns the render target introduced, like the quality of the final scaled
output, how to step outside of the logical size temporarily to draw some
things sharply at the native resolution, and loss of sub-pixel precision.

Fixes #8736.

test/testime.c

@@ -1109,7 +1109,7 @@ int main(int argc, char *argv[])
         SDL_Renderer *renderer = state->renderers[i];
         int icon_w = 0, icon_h = 0;
 
-        SDL_SetRenderLogicalPresentation(renderer, WINDOW_WIDTH, WINDOW_HEIGHT, SDL_LOGICAL_PRESENTATION_LETTERBOX, SDL_SCALEMODE_LINEAR);
+        SDL_SetRenderLogicalPresentation(renderer, WINDOW_WIDTH, WINDOW_HEIGHT, SDL_LOGICAL_PRESENTATION_LETTERBOX);
 
         ctx->window = window;
         ctx->renderer = renderer;