The sole purpose of `ActionController::Rendering#_normalize_args` is to
store the given block in `options[:update]`.  This behavior was added
long ago in 6923b392 (as [part of
`ActionController::Base#_normalize_options`][part-of]) to support RJS.
Rails no longer supports RJS, so this override is no longer necessary.

[part-of]: https://github.com/rails/rails/commit/6923b392b740f2346326634532b40cf24a0f26ef#diff-febf2f89e7c197d6a9a7077c96031c68b2b7ac4d8ce7ec634de92b164e5f69adR100