This was fixed initially in commit 7bbbd93 (https://phabricator.kde.org/D3796)
when the unittest was added, and broken later in commit bfd41a9
(https://phabricator.kde.org/D4193, bug 374913) which says Qt takes care
of taking the initial directory when calling selectUrl(). I cannot see
that in the Qt code, where selectUrl only calls selectFile_sys.
This breaks bug 374913 again (initial directory for remote files), but the
right fix for that is https://codereview.qt-project.org/235473