gc.c: drop special case for big hash/array

* gc.c (rb_gc_writebarrier): drop special case for big hash/array
  [Bug #9518]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45638 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-04-20

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45639 b2dd03c8-39d4-4d8f-98ff-823fe69b080e