gl-renderer: Don't use swap_buffers_with_damage with fan debug

Fan debug mode repaints the whole surface in order to clear any 'trails'
left over from previous fan paints. If this happens, fall back to using
regular eglSwapBuffers rather than eglSwapBuffersWithDamageEXT, since
the damage region we would pass will be too small.

Signed-off-by: Daniel Stone <daniels@collabora.com>