feat(nix/buildLisp): re-enable CCL

The problem went away once again, let's see how long it'll last this time.

As it turns out, CCL has a Unicode Standard conforming string
implementation that doesn't allow the use of (lone) surrogate code
points, requiring us to disable a test in cl-json which tested the
behavior of en- and decoding of such a (technically illegal) string.

Change-Id: I8bfa482934bbf94f86cecdde02d5c3d4e77950a5
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6204
Tested-by: BuildkiteCI
Autosubmit: sterni <sternenseemann@systemli.org>
Reviewed-by: tazjin <tazjin@tvl.su>

nix/buildLisp/default.nix

@@ -154,8 +154,7 @@ let
           let
             implementation = old.implementation or defaultImplementation;
             brokenOn = old.brokenOn or [ ];
-            # TODO(sterni): https://github.com/Clozure/ccl/issues/405
-            targets = lib.subtractLists (brokenOn ++ [ "ccl" implementation.name ])
+            targets = lib.subtractLists (brokenOn ++ [ implementation.name ])
               (builtins.attrNames impls);
           in
           {