Remove unused AV helper fixtures from e10a2531

Several fixtures for helpers are removed. They were introduced in
ActionView by @strzalek but never referenced in any test.
Bust the template digest cache key when details are changed

Since the lookup details will influence which template is resolved, they
need to be included in the cache key -- otherwise two different
templates may erroneously share the same digest value.
Fix incorrect assert_redirected_to failure message

In some instances, `assert_redirected_to` assertion was returning an
incorrect and misleading failure message when the assertion failed.
This was due to a disconnect in how the assertion computes the redirect
string for the failure message and how `redirect_to` computes the
string that is actually used for redirection.

I made the `_compute_redirect_to_loaction` method used by `redirect_to`
public and call that from the method `assert_redirect_to` uses to
calculate the URL.

The reveals a new test failure due to the regex used by
`_compute_redirect_to_location` allow `_` in the URL scheme.
Fix regex used to find URI schemes in redirect_to

The previous regex was allowing `_` in the URI scheme, which is not
allowed by RFC 3986. This change brings the regex in line with the RFC.
Merge pull request #10362 from derekprior/dp-fix-assert-redirect-to

Fix incorrect assert_redirected_to failure message
Run Tests against JRuby master

Many of the failing tests in rails test suite fail because of missing encoding support, example #11739


And according to recent announcement, lot of encoding issues have been fixed in current master.  http://ruby.11.x6.nabble.com/Big-encoding-patches-landed-on-master-td4993719.html


So lets test against JRuby master & incase there are still bugs. it would be easier to report them to JRuby.
Merge pull request #12294 from gaurish/patch-1

Run Tests against JRuby master
Allow failures in jruby-head
Merge pull request #12295 from gaurish/patch-2

Allow failures in jruby-head
Drying up method_missing code
Initializing Codepoint object with default values
mention controller test base class in testing guide. [ci skip]
Allow attaching to AS::Notifications namespace up front

Before, you were required to attach *after* adding the methods to the
class, since the attachment process needed the methods to be present.

With this change, any new method will also be attached to the configured
namespace.
Fix: Remove broken link on rails 3 guide

As raised in https://github.com/rails/rails/issues/12300
[ci skip]
Merge pull request #12299 from hitendrasingh/code_refactor

DRYing up method_missing code; Initializing Codepoint object with default values
Merge pull request #12285 from dasch/dasch/allow-attaching-up-front

Allow attaching to AS::Notifications namespace up front
Merge pull request #11452 from dasch/dasch/details-in-digestor-cache-key

Bust the template digest cache key when details are changed
Merge pull request #12301 from Gazler/guide_3_0_release_notes_broken_link

Documentation Fix: Remove broken link on rails 3 guide

Closes #12300
Merge pull request #12232 from claudiob/delete-unused-helper-fixtures

Remove unused AV helper fixtures from e10a2531