AccessorPairs containing only holes are maps were handled incorrectly.

BUG=v8:2153
TEST=mjsunit/regress/regress-2153.js

Review URL: https://chromiumcodereview.appspot.com/10453054

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11672 ce2b1a6d-e550-0410-aec6-3dcde31c8c00