file_rename.yml: allow running this on mswin/mingw

Suggested by MSP-Grep:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/87883

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63914 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

benchmark/file_rename.yml

@@ -7,9 +7,9 @@ benchmark:
     max = 100_000
     tmp = [ Tempfile.new('rename-a'), Tempfile.new('rename-b') ]
     a, b = tmp.map { |x| x.path }
+    tmp.each { |t| t.close } # Windows can't rename files without closing them
     max.times do
       File.rename(a, b)
       File.rename(b, a)
     end
-    tmp.each { |t| t.close! }
 loop_count: 1