[nix] Disable lix tests

nix/overlays/lix.nix

@@ -3,6 +3,10 @@
     postPatch = (oldAttrs.postPatch or "") + ''
       substituteInPlace src/libmain/shared.cc \
         --replace-fail "(Lix, like Nix)" "but for lesbians"
-      '';
+    '';
+
+    # WARNING: This greatly assumes that lix will never merge a CL that breaks
+    # the tests. But I choose to disable them anyway because the build time is faster
+    doCheck = false;
   });
 })