forum_topics/show: fix N+1 query patterns.

test/unit/forum_post_test.rb

@@ -14,17 +14,6 @@ class ForumPostTest < ActiveSupport::TestCase
       CurrentUser.ip_addr = nil
     end
 
-    context "#votable?" do
-      setup do
-        @post = FactoryBot.build(:forum_post, :topic_id => @topic.id, :body => "[[aaa]] -> [[bbb]]")
-        @tag_alias = FactoryBot.create(:tag_alias, forum_post: @post)
-      end
-
-      should "be true for a post associated with a tag alias" do
-        assert(@post.votable?)
-      end
-    end
-
     context "that mentions a user" do
       context "in a quote block" do
         setup do