Bugfix: dependent code field in AllocationSite was keeping code objects alive even after context death. (Chromium issue 320532)

Fixed data view accessors to throw execptions on offsets bigger than size_t. (issue 3013)

Performance and stability improvements on all platforms.

git-svn-id: http://v8.googlecode.com/svn/trunk@17859 ce2b1a6d-e550-0410-aec6-3dcde31c8c00