MIPS: Use compare nil ic only for non-strict equality.
MIPS: Use compare nil ic only for non-strict equality.

Port r15045 (cce366f)

Original commit message:
Strict-equality only has one check and cannot deopt. Should therefore not be part of the stub.

BUG=

Review URL: https://codereview.chromium.org/16690008
Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@15050 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

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