Address intermittent CI failure due to non-determined sort order

https://buildkite.com/rails/rails/builds/76112#1aa6023d-f58e-4c3e-96cc-027e36f2f415/973-984

Author: kamipo

activerecord/test/cases/json_serialization_test.rb

@@ -301,7 +301,7 @@ def test_should_allow_options_for_hash_of_authors
 
   def test_should_be_able_to_encode_relation
     set_include_root_in_json(true) do
-      authors_relation = Author.where(id: [@david.id, @mary.id])
+      authors_relation = Author.where(id: [@david.id, @mary.id]).order(:id)
 
       json = ActiveSupport::JSON.encode authors_relation, only: :name
       assert_equal '[{"author":{"name":"David"}},{"author":{"name":"Mary"}}]', json