Fix default_url_options example in i18n guide [ci skip]
Merge pull request #14564 from killthekitten/patch-2

Fix default_url_options example in i18n guide
In Active Record Querying guide, currently `Merging of scopes` section uses a concept of default scope in its example before it is introduced in the following section titled `Applying a default scope`.

It makes more sense to switch the ordering to introduce default scopes (`Applying a default scope`) first and then go into `Merging of scopes` section where it is used.
Add ConnectionHelper to refactor tests.
Merge pull request #14576 from ariabov/scope_sections_reordering

Change order of scope subsections in Active Record Querying guide [ci skip]
Treat blank UUID values as nil
Merge branch 'lavrovdv-patch-1'
Merge pull request #14561 from tgxworld/refactor_run_without_connection

Add ConnectionHelper to refactor tests.
Fix error when using `with_options` with lambda.

It was causing error when using `with_options` passing a lambda as its
last argument.

    class User < ActiveRecord::Base
      with_options dependent: :destroy do |assoc|
        assoc.has_many :profiles, -> { where(active: true) }
      end
    end

It was happening because the `option_merger` was taking the last
argument and checking if it was a Hash. This breaks the HasMany usage,
because its last argument can be a Hash or a Proc.

As the behavior described in this test:
https://github.com/rails/rails/blob/master/activesupport/test/option_merger_test.rb#L69
the method will only accept the lambda, this way it will keep the expected behavior. See 9eaa0a34