* iseq.c (iseqw_mark): as wrapped iseq is isolated from the call
stack, it needs to take care of its parent and ancestors, so
that they do not become orphans. [ruby-core:72620] [Bug #11928]
* iseq.c (rb_iseq_mark): mark parent iseq to prevent dynamically
generated iseq by eval from GC. [ruby-core:72620] [Bug #11928]
merge revision(s) 53514,53524: [Backport #11928]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@54405 b2dd03c8-39d4-4d8f-98ff-823fe69b080e