Set the proper instance-type on HAllocate in BuildFastLiteral

BUG=chromium:284577
R=hpayer@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23480094

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16790 ce2b1a6d-e550-0410-aec6-3dcde31c8c00