use the cached arel table

activerecord/lib/active_record/associations/join_dependency/join_base.rb

@@ -18,7 +18,7 @@ def aliased_prefix
         end
 
         def table
-          Arel::Table.new(table_name, arel_engine)
+          base_klass.arel_table
         end
 
         def aliased_table_name

activerecord/lib/active_record/associations/join_dependency/join_part.rb

@@ -19,7 +19,7 @@ class JoinPart # :nodoc:
         # association.
         attr_reader :base_klass, :children
 
-        delegate :table_name, :column_names, :primary_key, :arel_engine, :to => :base_klass
+        delegate :table_name, :column_names, :primary_key, :to => :base_klass
 
         def initialize(base_klass, parent)
           @base_klass = base_klass