MIPS: Only use Type for compiling load handlers.

Port r18025 (74fc739)

BUG=

Review URL: https://codereview.chromium.org/83913002

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18032 ce2b1a6d-e550-0410-aec6-3dcde31c8c00