`alias_attribute` used to define a "jump method", e.g.
`alias_attribute :foo, :bar` was pretty much a macro to generate

```ruby
def foo
  bar
end
```

This is convienient because it's easy, it doesn't impose an order
of declaration or anything like that.

But it's also much less efficient than a true `alias_method`.

It also used to cause cache size explosion which we fixed in
rails#52118, but making it behave
like Ruby's `alias_method`, by doing a real alias.

But this breaks some expectations (literally from the documentation):

```ruby
  attr_accessor :name
  attribute_method_suffix '_short?'
  define_attribute_methods :name

  alias_attribute :nickname, :name
```

Here we're not supposed to alias a generated method, but a user defined one.

So this assumption can only hold for Active Record, not Active Model.