Refactor `visit_ChangeColumnDefinition`

`visit_ChangeColumnDefinition` is the same "CHANGE column_name " + `visit_ColumnDefinition(o)`.
Because called `create_table_definition` any value in also https://github.com/rails/rails/blob/b599f99281d54047751e48789c44b73ccaec124c/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb#L976, I think better to the second and third argument has a default value.