tests: Null-terminate arrays for compatibility test of uint8 and uchar
tests: Null-terminate arrays for compatibility test of uint8 and uchar

Fixes https://gitlab.gnome.org/GNOME/vala/issues/809

GNOME/vala,frida/vala,frida/vala,GNOME/vala,frida/vala,frida/vala,GNOME/vala,GNOME/vala,frida/vala