MIPS: Restructure the IC / Handler compilers

Port r22622 (319e3252)

BUG=
R=paul.lind@imgtec.com

Review URL: https://codereview.chromium.org/414303003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22626 ce2b1a6d-e550-0410-aec6-3dcde31c8c00