Fix overflow in TypedArray initialization function

BUG=chromium:319120
TEST=test/mjsunit/regress/regress-319120.js
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/61753013

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17711 ce2b1a6d-e550-0410-aec6-3dcde31c8c00