The previous implementation in Accessors::ArraySetLength failed when array length was set through StoreIC_ArrayLength. But that stub and the accessor both delegate to JSArray::SetElementsLength, so moving the code there allows notifications to be sent in both cases.

Review URL: https://codereview.chromium.org/11275292
Patch from Adam Klein <adamk@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12962 ce2b1a6d-e550-0410-aec6-3dcde31c8c00