test_fileutils.rb: cache distinct UIDs
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57645 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_fileutils.rb: cache distinct UIDs
constants at initialization. assume no UIDs will be
added/removed during tests.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57645 b2dd03c8-39d4-4d8f-98ff-823fe69b080e