chez: Disable on aarch64-linux

There is no "arm64" machine, and using "arm32le" does not work.

pkgs/development/compilers/chez/default.nix

···
     homepage    = https://cisco.github.io/ChezScheme/;
     license     = stdenv.lib.licenses.asl20;
     platforms   = stdenv.lib.platforms.unix;
+    badPlatforms = [ "aarch64-linux" ];
     maintainers = with stdenv.lib.maintainers; [ thoughtpolice ];
   };
 }