Ruby

test_case.rb: fix multiple load

• lib/rubygems/test_case.rb (teardown): do not delete features
  loaded from the original load paths, the same libraries should
  be loaded again when the same features are required.
  [ruby-dev:49031] [Bug #11222]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51138 b2dd03c8-39d4-4d8f-98ff-823fe69b080e