Remove redundant flags for array buffer and typed arrays.

These flags are a no-op for a while, we kept them just because
Blink used to set them. After
https://src.chromium.org/viewvc/blink?revision=158187 they can be safely
removed.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/24267026

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16928 ce2b1a6d-e550-0410-aec6-3dcde31c8c00