Do not re-save destroyed association on saving parent object

Closes #11450

activerecord/lib/active_record/autosave_association.rb

@@ -343,6 +343,7 @@ def save_collection_association(reflection)
           end
 
           records.each do |record|
+            next if record.destroyed?
 
             saved = true
 

activerecord/test/cases/autosave_association_test.rb

@@ -705,6 +705,13 @@ def test_should_destroy_has_many_as_part_of_the_save_transaction_if_they_were_ma
     ids.each { |id| assert_nil klass.find_by_id(id) }
   end
 
+  def test_should_not_resave_destroyed_association
+    @pirate.birds.create!(name: :parrot)
+    @pirate.birds.first.destroy
+    @pirate.save!
+    assert @pirate.reload.birds.empty?
+  end
+
   def test_should_skip_validation_on_has_many_if_marked_for_destruction
     2.times { |i| @pirate.birds.create!(:name => "birds_#{i}") }