MIPS: Refactoring Store ICs. A first step towards polymorphic store ICs.

Port r13934 (656ce093)

BUG=

Review URL: https://codereview.chromium.org/12603003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13942 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
MIPS: Fix AssertName() in MacroAssembler.

This commit fixes several debug mode test failures.

BUG=mjsunit/keyed-call-generic,mjsunit/keyed-call-ic

Review URL: https://codereview.chromium.org/12693012

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13943 ce2b1a6d-e550-0410-aec6-3dcde31c8c00