Ruby

merge revision(s) ea42423908ed055f9039b1dce6e9a232a3b2dd90: [Backport #15887]
Keep vm->orig_progname alive

 `vm->orig_progname` can be different from `vm->progname` when user code assigns to `$0`. While `vm->progname` is kept alive by the global table, nothing marked `vm->orig_progname`. [Bug #15887] 

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67761 b2dd03c8-39d4-4d8f-98ff-823fe69b080e