X87: change the float max/min operation.

X87: change the float max/min operation when operands.

 This CL fixes the following situations:
    1, Operands are -0.0 or 0.0. it always return right value.
    1, Operands contains NaN. it always return right value.

BUG=

Committed: https://crrev.com/68020ce5467d2ced9484659d1afdb59a7a9e3741
Cr-Commit-Position: refs/heads/master@{#29407}

[chunyang.dai, 2015-06-30 09:15:35]

chunyang.dai@intel.com changed reviewers:
+ weiliang.lin@intel.com

[chunyang.dai, 2015-06-30 09:15:35]

PTAL.

[Weiliang, 2015-07-01 11:01:12]

The CQ bit was checked by weiliang.lin@intel.com

[Weiliang, 2015-07-01 11:01:13]

lgtm

[commit-bot: I haz the power, 2015-07-01 11:01:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1214893004/1

[commit-bot: I haz the power, 2015-07-01 11:29:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-01 11:29:18]

Patchset 1 (id:??) landed as
https://crrev.com/68020ce5467d2ced9484659d1afdb59a7a9e3741
Cr-Commit-Position: refs/heads/master@{#29407}