tests: fix glib tests with newest glib
tests: fix glib tests with newest glib

g_filename_from_utf8() was recently fixed to return filenames
instead of bytes.
See https://bugzilla.gnome.org/show_bug.cgi?id=756128

GNOME/pygobject,GNOME/pygobject,pexip/pygobject,pexip/pygobject,pexip/pygobject,GNOME/pygobject