Ruby

do not close FSs explicitly.

• test/ruby/test_dir.rb: r67159 closes all files explicitly
  but this change breaks attempt of this test introduced at
  r56467. Try another solution which removes all references
  from an Array with #clear.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67161 b2dd03c8-39d4-4d8f-98ff-823fe69b080e