MIPS: Reland 10216 - Optimize the equality check case of ICCompare stubs.

MIPS: Reland 10216 -  Optimize the equality check case of ICCompare stubs.

Port r10219 (56686b).

Original commit message:

Now with arm and x64 support. Additionally, added default unreachable case to switch statement in CompareIC::TargetState to make win and mac compilers happy.

Reviewer guide:
This is an exact copy of 10216 except:
src/arm/*
src/x64/*
src/ic.cc (added default case to swith in CompareIC::TargetState)

BUG=
TEST=
Review URL: http://codereview.chromium.org/8896022

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10232 ce2b1a6d-e550-0410-aec6-3dcde31c8c00