Disable Smi representation support for HMathMinMax
Disable Smi representation support for HMathMinMax

because it's incomplete on x64.

BUG=v8:2808
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/20690002

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@15893 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

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