MIPS: Allow setting debugger breakpoints on CompareNilICs

Port r14487 (022d1fc3)

BUG=

Review URL: https://codereview.chromium.org/14662002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14509 ce2b1a6d-e550-0410-aec6-3dcde31c8c00