Merge pull request #13983 from hsbt/remove-warning

use File.exist? instead of File.exists?

actionpack/test/dispatch/static_test.rb

@@ -144,7 +144,7 @@ def with_static_file(file)
 
       yield file
     ensure
-      File.delete(path) if File.exists? path
+      File.delete(path) if File.exist? path
     end
 end