The porting of array allocation in generated code from ia32 to x64 wrongly assumed that a smi contained the actual number times 2. Removed the constant times_half_pointer_size, as it will probably not be needed.
Review URL: http://codereview.chromium.org/596084

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3845 ce2b1a6d-e550-0410-aec6-3dcde31c8c00