Fix an error for `Layout/BlockAlignment` when using Ruby 3.1.0-dev
Fix an error for `Layout/BlockAlignment` when using Ruby 3.1.0-dev

This PR fixes the following build error.

```console
% bundle exec rspec ./spec/rubocop/cop/layout/block_alignment_spec.rb:222
(snip)

      # ./lib/rubocop/cop/layout/block_alignment.rb:97:in `start_for_block_node'
      # ./lib/rubocop/cop/layout/block_alignment.rb:82:in `on_block'
      # ./lib/rubocop/cop/commissioner.rb:100:in `public_send'
      # ./lib/rubocop/cop/commissioner.rb:100:in `block (2 levels) in trigger_responding_cops'
      # ./lib/rubocop/cop/commissioner.rb:160:in `with_cop_error_handling'
      # ./lib/rubocop/cop/commissioner.rb:99:in `block in trigger_responding_cops'
```

https://app.circleci.com/pipelines/github/rubocop/rubocop/5414/workflows/4a7e4b81-7380-41e5-8ede-e28d9160010d/jobs/201236

I reported on this change of behavior.
https://bugs.ruby-lang.org/issues/18268

And it was due to the following change.
https://github.com/ruby/ruby/pull/1509

This PR will be changed to the cop logic that is not affected by the above Ruby 3.1.0-dev change.

tejasbubane/rubocop,maxjacobson/rubocop,rrosenblum/rubocop,maxjacobson/rubocop,tejasbubane/rubocop,maxjacobson/rubocop,rrosenblum/rubocop,tejasbubane/rubocop,rrosenblum/rubocop