test_io.rb: defer f_type
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45783 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_io.rb: defer f_type
File::Statfs#type call which may not be implemented, to mitigate
errors on platforms where SEEK_DATA is available but f_type in
struct statfs is not. [ruby-dev:48154] [Bug #9789]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45783 b2dd03c8-39d4-4d8f-98ff-823fe69b080e