from excludes directory names. test-mjit-wait / test-mjit are combined
and distributed as mjit-test1 and mjit-test2 now.

So the subdirectory names are changed to option names, --jit and --jit-wait.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65766 b2dd03c8-39d4-4d8f-98ff-823fe69b080e