Fix brittle tests which were relying on the error message text from mysql2 gem

Uses queue adapter_method instead of ActiveJob::Base.queue_adapter

Change ActiveJob::Base.queue_adapter to use queue_adapter method to make test code consistent.

Use Hash#compact and Hash#compact! from Ruby 2.4

remove assets config from `new_framework_defaults` if `--skip-sprockets` is true

If `sprockets` is not loaded, `Rails.application.config.assets` is not defined.

* Put a blank line after :call-seq: otherwise it will think the whole test
is the call seq.
* Improve some text.
* Use some rdoc formatting.
* Restores the documentation of table_name_prefix.

[ci skip]

Fix model schema doc strings

Fix typo in Upgrading Ruby on Rails Guide [ci skip]

update description of Etag [ci skip]

The document is written with "only generate weak", but it can also be used to
strong etag.
Also, add missing entory for #24387

The first release note entry mentioned #on_weekday?, but that was only
added by the second PR mentioned there. To simplify reading the notes
just merge the two, since they are related methods. [ci skip]

Small grammar fix for #26867

[ci skip]

- Followup of fda5afeb

- These tests were fixed earlier on master in https://github.com/rails/rails/commit/f13ec72664fd13d33d617103ca964a7592295854.
- They started failing in first place due to change in https://github.com/brianmario/mysql2/commit/f14023fcfee9e85e6fc1b0e568048811518f8c23.
- They will fail again when the message is changed in mysql2 so let's
  not rely on the error message.

- Ruby 2.4 has added Hash#compact and Hash#compact! so we can use it
  now.
- Reference: https://bugs.ruby-lang.org/issues/11818 and https://bugs.ruby-lang.org/issues/12863.

Add info about updating locking column value

[ci skip]
Follow #26050

This reverts commit 671eb742.

This is not a change we would like moving forward.

Revert #26826 and add documentation

This reverts commit a01cf703 as explained in the comment to #26826:

Realized that this PR caused the following warning in Travis CI:

```
/home/travis/build/rails/rails/activesupport/lib/active_support/dependencies.rb:293: warning: loading in progress, circular require considered harmful - /home/travis/build/rails/rails/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
```

Indeed, `active_support/core_ext/hash/indifferent_access.rb` **needs** to require `active_support/hash_with_indifferent_access.rb` in order to access the class `ActiveSupport::HashWithIndifferentAccess`.

The other way around, though, is not _strictly_ required, unless someone tries (like I did in the [gist above](https://gist.github.com/claudiob/43cc7fe77ff95951538af2825a71e5ec)) to use `ActiveSupport::HashWithIndifferentAccess` by only requiring `active_support/hash_with_indifferent_access.rb` without first requiring `active_support/core_ext/hash/indifferent_access.rb`.

I think the solution to this is to revert this PR and instead change the documentation to explicitly state that **developers should not require 'active_support/hash_with_indifferent_access'** if all they want is to use `ActiveSupport::HashWithIndifferentAccess` – instead they should require `active_support/core_ext/hash/indifferent_access.rb`.

Refactored ActiveModel::Type tests into their own files

Convert ActionController::Parameters to a hash in button_to

Fix regression caused due to removal of select method from CollectionAssociation

- CollectionAssociation#select was removed in
  https://github.com/rails/rails/pull/25989 in favor of
  QueryMethods#select but it caused a regression when passing arguments
  to select and a block.
- This used to work earlier in Rails 4.2 and Rails 5. See gist
  https://gist.github.com/prathamesh-sonpatki/a7df922273473a77dfbc742a4be4b618.
- This commit restores the behavior of Rails 4.2 and Rails 5.0.0 to
  allow passing arguments and block at the same time but also deprecates
  it.
- Because, these arguments do not have any effect on the output of
  select when select is used with a block.
- Updated documentation to remove the example passing arguments and
  block at the same time to `CollectionProxy#select`.

Fix `ActiveSupport::TimeZone#strptime` cannot parse timestamps (%Q, %s)

Add missing require in active_support/hash_with_indifferent_access.rb 

Lazy-load blade for actioncable tests; no blade on JRuby.

Soften this test since YAML.dump may produce keys in other orders.

We need to use on_load so that plugins will get the same functionality