Require action_view explicitly in AC::Base
Merge pull request #13232 from strzalek/av-missing-requires

Require action_view explicitly in AC::Base
Upgrade minitest version

We made a change in #13213 that depends on a new file that's only in
minitest 5.1.0+, so the version should be updated.
Merge pull request #13231 from chancancode/upgrade_minitest

Upgrade minitest version