test_io.rb: fix IO#advise on aarch64-linux
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53034 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
test_io.rb: fix IO#advise on aarch64-linux
aarch64-linux returns ESYS.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53034 b2dd03c8-39d4-4d8f-98ff-823fe69b080e