* gc.c: move rb_objspace_t::flags::gc_stressfull after during_gc
  to make accesssing both parameters easy.
* gc.c (heap_get_freeobj): add LIKELY() hint.
* gc.c (heap_get_freeobj_from_next_freepage): ditto.
* gc.c (newobj_of): check both parameters at once for exceptional
  case.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47467 b2dd03c8-39d4-4d8f-98ff-823fe69b080e