compile.c: wrap funcptr

* compile.c (iseq_build_from_ary_body): enclose funcptr with
  Integer as raw pointer cannot appear in an Array.

* iseq.c (iseq_data_to_ary): extract funcptr from Integer.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48863 b2dd03c8-39d4-4d8f-98ff-823fe69b080e