test/t_wembed: add parent widget to fix crash
test/t_wembed: add parent widget to fix crash

Crash bug caused by 80df5b7172d090b26042d6bed4041b333c3a3d47

CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy,CM4all/beng-proxy