Win 64 C call ABI implementation requires space allocated on stack for four
argument registers, even when passing fewer arguments in registers.

Review URL: http://codereview.chromium.org/2365001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4748 ce2b1a6d-e550-0410-aec6-3dcde31c8c00