add test for [ruby-dev:44049].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32448 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

bootstraptest/test_objectspace.rb

@@ -32,3 +32,9 @@ assert_normal_exit %q{
     end
   }
 }, '[ruby-dev:31985]'
+
+assert_normal_exit %q{
+  ObjectSpace.define_finalizer("") do
+    Mutex.new.lock
+  end
+}, '[ruby-dev:44049]'