Added SDL_FlipSurface() to flip a surface vertically or horizontally

Fixes https://github.com/libsdl-org/SDL/issues/8857

src/dynapi/SDL_dynapi.sym

@@ -964,6 +964,7 @@ SDL3_0.0.0 {
     SDL_GetHapticInstanceID;
     SDL_GetHapticName;
     SDL_ReadSurfacePixel;
+    SDL_FlipSurface;
     # extra symbols go here (don't modify this line)
   local: *;
 };