Version 3.30.18 (based on bleeding_edge revision r24862)

Narrow cases where Sparse/Smart versions of Array methods are used (issues 2615, 3612, 3621).

Shrink new space in idle notification (Chromium issue 424423).

Performance and stability improvements on all platforms.

git-svn-id: https://v8.googlecode.com/svn/trunk@24879 ce2b1a6d-e550-0410-aec6-3dcde31c8c00