[gtkmm] tests/builder: Drop .ui properties gone in GTK 4

[Daniel Boles <dboles src gnome org>]

commit ff3e8dc6deb885602a1b490f1dc314ba2740f567
Author: Daniel Boles <dboles src gnome org>
Date:   Sun Dec 16 23:38:39 2018 +0000

    tests/builder: Drop .ui properties gone in GTK 4
    
    Widget:visible and the Box child properties were all removed ages ago.

 tests/builder/main.cc | 8 --------
 1 file changed, 8 deletions(-)
---
diff --git a/tests/builder/main.cc b/tests/builder/main.cc
index 2a9635bd..562d304d 100644
--- a/tests/builder/main.cc
+++ b/tests/builder/main.cc
@@ -36,32 +36,25 @@ const char gladefile[] =
     "<property name='default_height'>150</property>"
     "<child>"
       "<object class='GtkBox' id='vbox'>"
-        "<property name='visible'>True</property>"
         "<property name='can_focus'>False</property>"
         "<property name='orientation'>vertical</property>"
         "<child>"
           "<object class='GtkButton' id='derived_button'>"
             "<property name='label' translatable='yes'>DerivedButton</property>"
-            "<property name='visible'>True</property>"
             "<property name='can_focus'>True</property>"
             "<property name='receives_default'>True</property>"
           "</object>"
           "<packing>"
-            "<property name='expand'>False</property>"
-            "<property name='fill'>True</property>"
             "<property name='position'>0</property>"
           "</packing>"
         "</child>"
         "<child>"
           "<object class='GtkButton' id='standard_button'>"
             "<property name='label' translatable='yes'>Gtk::Button</property>"
-            "<property name='visible'>True</property>"
             "<property name='can_focus'>True</property>"
             "<property name='receives_default'>True</property>"
           "</object>"
           "<packing>"
-            "<property name='expand'>False</property>"
-            "<property name='fill'>True</property>"
             "<property name='position'>1</property>"
           "</packing>"
         "</child>"
@@ -70,7 +63,6 @@ const char gladefile[] =
   "</object>"
   "<object class='GtkButton' id='orphaned_button'>"
     "<property name='label' translatable='yes'>Gtk::Button</property>"
-    "<property name='visible'>True</property>"
     "<property name='can_focus'>True</property>"
     "<property name='receives_default'>True</property>"
   "</object>"