Delegate respond_to? in ActionView::Helpers::ControllerHelper

Create `rails@localhost` user on travis ci

We've seen consistent failures in the Active Support
builds since removing the version lock in f5f213cc.

This change was introduced by #18109. The intent of that change was to
specifically apply `unscoped`, not to allow all changes to
`current_scope` to affect the join. The idea of allowing `current_scope`
to affect joins is interesting and potentially more consistent, but has
sever problems associated with it. The fact that we're specifically
stripping out joins indicates one such problem (and potentially leads to
invalid queries).

Ultimately it's difficult to reason about what `Posts.joins(:users)`
actually means if it's affected by `User.current_scope`, and it's
difficult to specifically control what does or doesn't get added. If we
were starting from scratch, I don't think I'd have `joins` be affected
by `default_scope` either, but that's too big of a breaking change to
make at this point.

With this change, we no longer apply `current_scope` when bringing in
joins, with the singular exception of the motivating use case which
introduced this bug, which is providing a way to *opt-out* of having the
default scope apply to joins.

Fixes #29338.

Backported the wrong expected output in 631c596c.

This reverts commit 92a66aa0.

Revert "Revert "Backport test runner loading to 5-0-stable.""

This reverts commit 5d7002bf.

Fix mattr_reader usage to 5.1 style.

Fix root not being defined on Travis.

This reverts commit 796a1cf0.

This reverts commit 7e53003d.

By making the Rails minitest behave like a standard minitest plugin
we're much more likely to not break when people use other minitest
plugins. Like minitest-focus and pride.

To do this, we need to behave like minitest: require files up front
and then perform the plugin behavior via the at_exit hook.
This also saves us a fair bit of wrangling with test file loading.

Finally, since the environment and warnings options have to be applied
as early as possible, and since minitest loads plugins at_exit, they
have to be moved to the test command.

* Don't expect the root method.

It's likely this worked because we eagerly loaded the Rails minitest plugin
and that somehow defined a root method on `Rails`.

* Assign a backtrace to failed exceptions.

Otherwise Minitest pukes when attempting to filter the backtrace (which
Rails' backtrace cleaner then removes).

Means the exception message test has to be revised too.

This is likely caused by the rails minitest plugin now being loaded for
these tests and assigning a default backtrace cleaner.

Now that the parameters configurations are only loaded when
ActionController::Base is we need to foce them to load in our tests. In
an application this is not needed since every request already load the
controllers.

We need to configure it only when ActionController::Base is loaded
otherwise configs on initializers will not work.

Closes #29527.

Allow the use of Bundler 2.0

Fix the class name --> ActionController::Parameters [ci skip]

Fallback Parameters#to_s to Hash#to_s

Fix missing formats in route-set URLs

Calling `follow_redirect!` does not reset the `html_document`:

ActiveJob::Core#serialize stores provider_job_id (fixes #26581).

This was supposed to have been pushed to 5-1-stable.

This reverts commit 89b38068.

Don't wrap parameters if key already exists

Removed reference to unexisting methods:

Use of ParameterFilter no longer forces `request.filtered_parameters' class to be Hash

This reverts commit 6bb76f1a.

Fix `Relation#exists?` queries with query cache

Fixes FIXME: rb-inotify 0.99 has been released

Fix `dump_schema_information` with empty versions