* array.c (ary_memcpy): try to enable optimization.
  At least on my environments, I don't see any errors
  with many trials. Please tell us if you find any GC bugs.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42192 b2dd03c8-39d4-4d8f-98ff-823fe69b080e