Prefer the simple read/write File singleton methods

test/ruby/test_dir_m17n.rb

@@ -362,7 +362,7 @@ class TestDir_M17N < Test::Unit::TestCase
   def test_glob_encoding
     with_tmpdir do
       list = %W"file_one.ext file_two.ext \u{6587 4ef6}1.txt \u{6587 4ef6}2.txt"
-      list.each {|f| open(f, "w") {}}
+      list.each {|f| File.binwrite(f, "")}
       a = "file_one*".dup.force_encoding Encoding::IBM437
       b = "file_two*".dup.force_encoding Encoding::EUC_JP
       assert_equal([a, b].map(&:encoding), Dir[a, b].map(&:encoding))