MIPS: Before comparing input with a constant smi in GenerateRecordCallTarget(), make sure the input register is actually a smi.

Port r14547 (a2e764c7)

BUG=

Review URL: https://codereview.chromium.org/14597006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14548 ce2b1a6d-e550-0410-aec6-3dcde31c8c00