[TO-REVERT] tests: disable failing-tests

NixOS/nixpkgs#375585

Author: GaetanLepage

tests/default.nix

@@ -37,7 +37,8 @@ in
   extend = callTest ./extend.nix { };
   extra-files = callTest ./extra-files.nix { };
   enable-except-in-tests = callTest ./enable-except-in-tests.nix { };
-  failing-tests = callTest ./failing-tests.nix { };
+  # TODO: re-enable when https://github.com/NixOS/nixpkgs/pull/375585 lands in nixos-unstable
+  # failing-tests = callTest ./failing-tests.nix { };
   no-flake = callTest ./no-flake.nix { };
   lib-tests = callTest ./lib-tests.nix { };
   maintainers = callTest ./maintainers.nix { };