[glib: 2/4] Remove old tests not being built since 2012

[Philip Withnall <pwithnall src gnome org>]

commit b04cf01934b5def7f787631dd8d35e950e46df2d
Author: Xavier Claessens <xavier claessens collabora com>
Date:   Mon Jun 4 22:18:02 2018 -0400

    Remove old tests not being built since 2012
    
    Those tests are failing and are not built since commit d6a075b

 tests/gobject/ifacecheck.c   | 163 -----------------
 tests/gobject/ifaceinherit.c | 230 -----------------------
 tests/gobject/ifaceinit.c    | 421 -------------------------------------------
 3 files changed, 814 deletions(-)