* test/rubygems/test_require.rb (test_dash_i_beats_gems): create
temporary library directory under the temporary directory
created by Gem::TestCase#setup, not to leave garbages in the
default temporary directory.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53665 b2dd03c8-39d4-4d8f-98ff-823fe69b080e