Fix jt ruby-home

* The method was defined in Utilities and not Commands.

Author: eregon

tool/jt.rb

@@ -286,7 +286,6 @@ def ruby_home
     require_ruby_launcher!
     File.expand_path('../..', @ruby_launcher_realpath)
   end
-  alias_method :'ruby-home', :ruby_home
 
   def truffleruby!
     raise 'This command requires TruffleRuby.' unless truffleruby?
@@ -917,6 +916,10 @@ def launcher
     puts ruby_launcher
   end
 
+  define_method(:'ruby-home') do
+    puts ruby_home
+  end
+
   def build(*options)
     in_truffleruby_repo_root!
     project = options.shift