Fixes: #13445

Closes #13444

change CollectionAssociation's comments to say Association instead of AssociationProxy to match changes for 3.1 removing Association proxy.

Need to check if valud also respond_to :id before calling it, otherwise
things could explode.

[ci skip]

Previously, executing an insert SQL in PostgreSQL with a command like this:

    insert into articles(
      number)
    values(
      5152
    )

would not work because the adapter was unable to extract the correct articles table name.

Change most tests to make use of assert_raise returning the raised
exception rather than relying on a combination of flunk + rescue to
check for exception types/messages.

The changes in c4044b2f meant the tests would error on a fresh DB.

Assigning nil to a polymorphic belongs_to would nullify its _id field by
not its _type field.

Fixes failing test from c141dfc8.
Regression from 1678e959.

Ref: https://github.com/seattlerb/minitest/blob/master/History.txt

This change was necessary because the whitelist wouldn't work.
It would be painful for users trying to update their applications.

This blacklist intent to prevent odd bugs and confusion in code that call mutator
methods directely on the `Relation`.

Blast from the past, MySQL 4 era, when the password hashing style changed.

Using the name of an association in `where` previously worked only
if the value was a single `ActiveRecrd::Base` object. e.g.

    Post.where(author: Author.first)

Any other values, including `nil`, would cause invalid SQL to be
generated. This change supports arguments in the `where` query
conditions where the key is a `belongs_to` association name and the
value is `nil`, an `Array` of `ActiveRecord::Base` objects, or an
`ActiveRecord::Relation` object.

    # Given the Post model
    class Post < ActiveRecord::Base
      belongs_to :author
    end

    # nil value finds records where the association is not set
    Post.where(author: nil)
    # SELECT "posts".* FROM "posts" WHERE "posts"."author_id" IS NULL

    # Array values find records where the association foreign key
    # matches the ids of the passed ActiveRecord models, resulting
    # in the same query as Post.where(author_id: [1,2])
    authors_array = [Author.find(1), Author.find(2)]
    Post.where(author: authors_array)

    # ActiveRecord::Relation values find records using the same
    # query as Post.where(author_id: Author.where(last_name: "Emde"))
    Post.where(author: Author.where(last_name: "Emde"))

Polymorphic `belongs_to` associations will continue to be handled
appropriately, with the polymorphic `association_type` field added
to the query to match the base class of the value. This feature
previously only worked when the value was a single `ActveRecord::Base`.

    class Post < ActiveRecord::Base
      belongs_to :author, polymorphic: true
    end

    Post.where(author: Author.where(last_name: "Emde"))
    # Generates a query similar to:
    Post.where(author_id: Author.where(last_name: "Emde"), author_type: "Author")

db:test:clone and db:test:prepare use
ActiveRecord::Base. configurations, so we need to load the rails
environment, otherwise the config wont be in place.

also override drop_table in AbstractMySQLAdapter to properly drop
temporary tables without committing the transaction

* interpreted as a argument prefix

This will fix the [broken
test](https://github.com/rails/rails/commit/4a2650836680f51490e999c3c8441a2f9adff96e)
 `test_with_limiting_with_custom_select`.

The query's result was built in a hash with column name as key, if the
result have a duplicated column name the last value was
overriding the first one.

Add a bunch of Relation -> Array delegate methods to the whitelist. This won't last - aim to switch back to a blacklist for mutator methods.