test/ruby: independent from pathname

* test/ruby/test_dir.rb (TestDir#setup): remove dependency on pathname.

* test/ruby/test_rubyoptions.rb (TestRubyOptions#with_tmpchdir): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41753 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
dir.c: do_lstat alias

* dir.c (do_lstat): make an alias of do_stat instead of two same
  functions, when no lstat is available.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41754 b2dd03c8-39d4-4d8f-98ff-823fe69b080e