gc.c: no deletion in wmap_mark
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44149 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
gc.c: no deletion in wmap_mark
so that WeakMap can be non-shady.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44149 b2dd03c8-39d4-4d8f-98ff-823fe69b080e