Ruby » Ruby master

• gc.c (gc_mark_ptr): add a check code for #11244.
  It should be removed later. But we can remain this check
  because it is only a branch.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51010 b2dd03c8-39d4-4d8f-98ff-823fe69b080e