wsi/x11: xcb_wait_for_special_event failure is an error

wsi/x11: xcb_wait_for_special_event failure is an error

The only ways that function can return NULL are:

- the xcb connection was closed
- the window for the swapchain was destroyed
- the special event listener was unregistered from another thread
- malloc failure

All of these are permanent errors, the swapchain is no longer in a
usable state, so we should treat this as VK_ERROR_SURFACE_LOST_KHR.

Acked-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15558>