ext/objspace: remove OS.after_gc_start_hook= and move internal test
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44007 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
ext/objspace: remove OS.after_gc_start_hook= and move internal test
tracepoint re-entry
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44007 b2dd03c8-39d4-4d8f-98ff-823fe69b080e