Fix test helper method stub_licensed_features for JH features

What does this Issue do

stub_licensed_features is a helper method that helps mock feature license in test environment.

For feature license added only in JH, it will throw an ArgumentError that the feature license doesn't exist.

Proposal

stub_licensed_features depends on GitlabSubscriptions::Features::ALL_FEATURES .

Re-define ALL_FEATURES in JH to allow JH specific features to be found.

ee/spec/support/helpers/ee/license_helpers.rb

      def stub_licensed_features(features)
        missing_features = features.keys.map(&:to_sym) - GitlabSubscriptions::Features::ALL_FEATURES

        if missing_features.any?
          subject = missing_features.join(', ')
          noun = 'feature'.pluralize(missing_features.size)
          raise ArgumentError, "#{subject} should be defined as licensed #{noun}"
        end

      # ...

---

cc EM @prajnamas