autotests: Stabilize tests that create Xwayland windows
The order in which Xwayland surfaces are associated with X11 windows is undefined, meaning that we cannot assume that a newly created X11 window won't have a surface associated with it already.
The order in which Xwayland surfaces are associated with X11 windows is undefined, meaning that we cannot assume that a newly created X11 window won't have a surface associated with it already.