Do not include action_view/layouts

We don't need them. They'll be loaded automaticly if AV will be included
Fist stab on basic rendering
Move render_test to AV
Split rendering tests between AP & AV

All rendering test remain in AV. Head, ETag etc. test stay in AP
Remove unused fixtures and models from AP tests
Cleanup & reorganise rake tasks in AV
Add AP tests to runner
Move remaining layouts tests to AV
Move AP's capture tests to AV
Basic rendering test
Update AP changelog
Load HTML in ActionView not ActionPack

HTML Scanner is part of ActionView and it should be loaded along with it
Extend basic rendering, test it in railties
Describe BasicRendering shortly

[ci skip]
Move actionpack's controller tests
Move abstract's controller tests to AV

The ones that were actually testing AV functionality and should belong in there
Simplify if statements
Change description of BasicRendering#render

We're not dealing with templates here

[ci skip]
Fix formatting of error message

Make it oneliner
Merge pull request #12009 from wangjohn/fixtures_fix

Removing instances of string class_names in fixtures.