object.c: make remove_instance_variable public
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38114 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
object.c: make remove_instance_variable public
[Feature #6539]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38114 b2dd03c8-39d4-4d8f-98ff-823fe69b080e