Add I18n.locale for views cache
[Fixes #4673]
[Fixes #4678]

Conflicts:
	api/app/views/spree/api/shipments/small.v1.rabl
	frontend/spec/features/caching/products_spec.rb
Fix specs that were broken by f1658936aa021a9cded44d4df59eab0c884ac06e in 2-2-stable

Fix bad conflict resolution.

Fixes #4713