MIPS: Fix LoadIC calling convention.

MIPS: Fix LoadIC calling convention.

Port r15027 (3ffb343)

Original commit message:
The comments in ic-arm.cc::LoadIC indicated that the receiver should be
both in a register and on the stack. This isn't true in fact: the code
is careful to spill the receiver if needed.

This CL also fixes up a mistaken use of this convention in VisitYield.

BUG=

Review URL: https://codereview.chromium.org/16131004
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15048 ce2b1a6d-e550-0410-aec6-3dcde31c8c00