use locale specific order_by in simple bookmarker

don't cache a collation key for a different locale if
it switches across requests

test plan:
* specs run

refs #USERS-448

Change-Id: I411710bea4eb8755ac6fc6ad7de8e60956f081ab
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/231195
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Keith Garner <kgarner@instructure.com>
Reviewed-by: Mysti Lilla <mysti@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Clint Furse <cfurse@instructure.com>
Product-Review: James Williams <jamesw@instructure.com>

gems/bookmarked_collection/lib/bookmarked_collection/simple_bookmarker.rb

@@ -143,7 +143,9 @@ module BookmarkedCollection
     end
 
     def order_by
-      @order_by ||= Arel.sql(columns.map { |col| column_order(col) }.join(', '))
+      @order_by ||= {}
+      locale = defined?(Canvas::ICU) ? Canvas::ICU.locale_for_collation : :default
+      @order_by[locale] ||= Arel.sql(columns.map { |col| column_order(col) }.join(', '))
     end
 
     def column_order(col_name)