Remove force parent loading when counter cache child is created/destr…

…oyed

`association.increment_counters` and `association.decrement_counters`
works regardless of parent target is loaded or not.

Related 52e11e4.

activerecord/lib/active_record/counter_cache.rb

@@ -163,9 +163,7 @@ def _create_record(attribute_names = self.attribute_names)
         id = super
 
         each_counter_cached_associations do |association|
-          if send(association.reflection.name)
-            association.increment_counters
-          end
+          association.increment_counters
         end
 
         id
@@ -178,9 +176,7 @@ def destroy_row
           each_counter_cached_associations do |association|
             foreign_key = association.reflection.foreign_key.to_sym
             unless destroyed_by_association && destroyed_by_association.foreign_key.to_sym == foreign_key
-              if send(association.reflection.name)
-                association.decrement_counters
-              end
+              association.decrement_counters
             end
           end
         end

activerecord/test/cases/associations/belongs_to_associations_test.rb

@@ -578,7 +578,11 @@ def test_belongs_to_reassign_with_namespaced_models_and_counters
 
   def test_belongs_to_counter_after_save
     topic = Topic.create!(title: "monday night")
-    topic.replies.create!(title: "re: monday night", content: "football")
+
+    assert_queries(2) do
+      topic.replies.create!(title: "re: monday night", content: "football")
+    end
+
     assert_equal 1, Topic.find(topic.id)[:replies_count]
 
     topic.save!