MIPS: Make KeyedLoads from a sloppy arguments array use a handler.
MIPS: Make KeyedLoads from a sloppy arguments array use a handler.

Port r24120 (eed5963)

Original commit message:
Before, a custom stub was installed.

BUG=
R=paul.lind@imgtec.com

Review URL: https://codereview.chromium.org/594563003

git-svn-id: f98b9d40cb02301bc76fa9e1b46ee668158567fd@24126 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh