added re-creating renderer and textures when changing video vsync mode

When not using OpenGL renderer, changing video vsync mode requires
re-creating renderer and textures with changed vsync settings.

(This uses code for re-creating the screen that was a part of function
"ToggleFullscreenOrChangeWindowScalingIfNeeded()", but that was never
used after support for SDL 1.2 was removed with commit d3e24bbf.)