Autoload ActiveModel::StrictValidationFailed

Currently, if environment doesn’t eager load code, invoking this
constant before calling #valid? on a model instance results in a
NameError.

activemodel/lib/active_model.rb

@@ -48,6 +48,7 @@ module ActiveModel
 
   eager_autoload do
     autoload :Errors
+    autoload :StrictValidationFailed, 'active_model/errors'
   end
 
   module Serializers