wayland: fix testtooltips
wayland: fix testtooltips

On Wayland, for tooltips to work as expected, the type hint must be set
to tooltips, otherwise the popup window won't be translated as a
subsurface.

Fix the test do work as expected under Wayland.

Bugzilla: https://bugzilla.gnome.org/show_bug.cgi?id=759018

grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita