Version 3.28.3 (based on bleeding_edge revision r22006)

Grow heap slower if GC freed many global handles (Chromium issue 263503).

Performance and stability improvements on all platforms.

git-svn-id: https://v8.googlecode.com/svn/trunk@22025 ce2b1a6d-e550-0410-aec6-3dcde31c8c00