test/test_tmpdir.rb: Specify frozen_string_literal: true.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57408 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
2017-01-23 15:47:32 +00:00 · 2017-01-23 15:47:32 +00:00 · 0c9e2cf264
--- a/test/test_tmpdir.rb
+++ b/test/test_tmpdir.rb
@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'test/unit'
 require 'tmpdir'