knot-resolver: avoid a flaky test

The test is relatively sensitive on timing, so it can fail in case
a builder is heavily loaded.  In practice we occasionally see that
on *-darwin.  In distro such tests are more trouble than worth;
and we keep running these upstream anyway.

pkgs/servers/dns/knot-resolver/default.nix

@@ -90,7 +90,7 @@ unwrapped = stdenv.mkDerivation rec {
   doInstallCheck = with stdenv; hostPlatform == buildPlatform;
   nativeInstallCheckInputs = [ cmocka which cacert lua.cqueues lua.basexx lua.http ];
   installCheckPhase = ''
-    meson test --print-errorlogs
+    meson test --print-errorlogs --no-suite snowflake
   '';
 
   meta = with lib; {