Flatten the call stacks ActiveSupport::Callbacks produces, fix #18011.
PostgreSQL, Fix change detection caused by wrong data for bytea unescaping.

This showed up when running BinaryTest#test_load_save with the more
restrictive input string handling of pg-0.18.0.pre20141117110243.gem .

Bytea values sent to the server are in binary format, but are
returned back as escaped text. To fulfill the assumption that
type_cast_from_database(type_cast_for_database(binary)) == binary
we unescape only, if the value was really received from the server.
ActiveJob testing improvements

1. The :test adapter wasn't going through a full cycle of
serialize/deserialize when performing jobs. Now it does
2. Regular AJ tests were not run for the :test adapter. Now they are
3. ActiveJob::TestHelper uses assert_valid_keys but doesn’t requires
the file that implements that method. Now it does
Use more semantic method to check password
Tiny documentation fixes [ci skip]
 Fix description for application_name method - change simple to simply

 [ci skip]
Merge pull request #18258 from prathamesh-sonpatki/fix-application-name-description

 Fix description for application_name method - change simple to simply [ci skip]
Merge pull request #18256 from rohit/secure-password-tweak

Use more semantic method to authenticate password in SecurePassword
Remove this line which was added by accident [ci skip]
Ensures that primary_key method will return nil when multi-pk

When table has a composite primary key, the `primary_key` method for
sqlite3 and postgresql was only returning the first field of the key.

Ensures that it will return nil instead, as AR dont support composite pks.
Replace exhaustive list of helper methods with pointers to helper classes found
in the Action Dispatch Integration module. [ci skip]
Add implement integration test to Testing Guide. [ci skip]
Merge pull request #18259 from arthurnn/return_nil_on_multi_pk

Ensures that primary_key method will return nil when multi-pk
 Update CHANGELOG entry for #18070 [ci skip]

 - Improved wording of CHANGELOG entry for https://github.com/arthurnn/rails/commit/5acd24bbeae0e9e5e81e87b5929e17f35527b2ea.
Make "Testing Views" separate section, move "Setup and Teardown" into
functional testing section and implement :show, :destroy, and :update tests.

[ci skip]
Merge pull request #18261 from prathamesh-sonpatki/update-changelog

 Update CHANGELOG entry for #18070 [ci skip]
Merge branch 'master' of github.com:rails/rails [ci skip]
Move request tests after functional and before views, and move helper tests
after views. [ci skip]
Add result of running articles_routes_test and point to more information for
RoutingAssertions. [ci skip]
Replace exhaustive list of methods with pointer to API docs. [ci skip]