Dont mess with default order engines load

When copying migrations some engines might depend on schema from other
engine so we can't blindly reverse all railties collection as that would
affect the order they were originally loaded. This patch helps to only
apply the order from engines specified in `railties_order`
[Active Job] Try to deserialize with GlobalID only strings and globalids
Ship with rails-html-sanitizer instead.
extract updating all fixture cache to a method so we can lock later
Merge pull request #16756 from huoxito/dont-mess-railties-default-order

Dont mess with default order engines load (4.1.6.rc1 regression)
Merge pull request #16775 from kaspth/ship-secure-sanitizer

Ship with rails-html-sanitizer instead.
Active Job refactoring
Merge pull request #16787 from cristianbica/fix-globalid-deserialization

[Active Job] Try to deserialize with GlobalID only strings and globalids
Methods are not duplicable.
Merge pull request #16795 from Peeja/methods-are-not-duplicable

Methods are not duplicable.
Add support for ARIA attributes in tags
Merge pull request #16796 from ARIATeam/aria

Add support for ARIA attributes in tags
Extract data/aria attribute prefixes to a constant
code gardening in ActionController::Renderers

* Renames _handle_render_options to _render_to_body_with_renderer, which is more
  intention-revealing.

* The name of the dynamically generated method for a renderer with key :js was
  "_render_option_js".

  That name is too weak. :js is an option if you see the render argument as just
  a generic options hash, but in the context of renderers that's the renderer
  key, is what identifies the renderer.

  Now "_render_with_renderer_js" is generated instead, which is crystal clear.

* The name of the dynamically generated method for the renderer was constructed
  using string literals in a few places. That is now encapsulated in a method.

* Since we were on it, also removed a couple of redundant selfs.
Rename remaining :in / :at to :wait / :wait_until
[ci skip] Fix typo in rails guide for routing
get rid of shadowing warning when running tests AR and railtie tests.

Warning looked like this:

```
/Users/senny/Projects/rails/activerecord/lib/active_record/associations/association_scope.rb:142: warning: shadowing outer local variable - reflection
```
build fix, we have to reset the RACK_ENV as well.

This is a follow-up to ded17a4 to get the build passing on Travis.
As Travis has `ENV["RACK_ENV"]` set to `test` we need to reset that as well.
Enums shouldn't ruin people's anniversaries

Added a few more methods on Module/Class to the dangerous class methods
blacklist. (Technically, allocate and new are already protected currently because
we happen to redefine them in the current implantation.)

Closes #16792
Merge pull request #16799 from rramsden/fix-typo

[ci skip] Fix typo in rails guide for routing