MIPS: Fix Win32 buildbreak (caused by overriden methods that have disappeared while having the patch out for code review).

Port r18627 (c2ba7b25)

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/140203002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18631 ce2b1a6d-e550-0410-aec6-3dcde31c8c00