nixos/tests/fontconfig-default-fonts: switch to containers, don't use cantarell-fonts (#535675)

nixos/tests/fontconfig-default-fonts.nix

@@ -6,20 +6,19 @@
     jtojnar
   ];
 
-  nodes.machine =
+  containers.machine =
     { config, pkgs, ... }:
     {
       fonts.enableDefaultPackages = true; # Background fonts
       fonts.packages = with pkgs; [
         noto-fonts-color-emoji
-        cantarell-fonts
         twitter-color-emoji
         source-code-pro
         gentium
       ];
       fonts.fontconfig.defaultFonts = {
         serif = [ "Gentium" ];
-        sansSerif = [ "Cantarell" ];
+        sansSerif = [ "DejaVu Sans" ];
         monospace = [ "Source Code Pro" ];
         emoji = [ "Twitter Color Emoji" ];
       };
@@ -27,7 +26,7 @@
 
   testScript = ''
     machine.succeed("fc-match serif | grep '\"Gentium\"'")
-    machine.succeed("fc-match sans-serif | grep '\"Cantarell\"'")
+    machine.succeed("fc-match sans-serif | grep '\"DejaVu Sans\"'")
     machine.succeed("fc-match monospace | grep '\"Source Code Pro\"'")
     machine.succeed("fc-match emoji | grep '\"Twitter Color Emoji\"'")
   '';