Throw exception on invalid string length instead of OOM.

R=bmeurer@chromium.org
BUG=349329
LOG=Y

Review URL: https://codereview.chromium.org/199853004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20112 ce2b1a6d-e550-0410-aec6-3dcde31c8c00