[turbofan][arm64] Match fneg for -0.0 - x pattern.

[turbofan][arm64] Match fneg for -0.0 - x pattern.

Note that this patch add an extra bit to the ArchOpcodeField.

R=bmeurer@chromium.org

Committed: https://crrev.com/fe7441225100660d01e66ce3bcaefe368f62df81
Cr-Commit-Position: refs/heads/master@{#27494}

[baptiste.afsa1, 2015-03-26 16:27:36]

PTAL

[Benedikt Meurer, 2015-03-27 08:02:54]

Nice, thanks. LGTM

[Benedikt Meurer, 2015-03-27 08:03:00]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-03-27 08:03:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1013743006/1

[commit-bot: I haz the power, 2015-03-27 08:32:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-27 08:32:39]

Patchset 1 (id:??) landed as
https://crrev.com/fe7441225100660d01e66ce3bcaefe368f62df81
Cr-Commit-Position: refs/heads/master@{#27494}

[Yang, 2015-03-27 09:11:32]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1041633002/ by yangguo@chromium.org.

The reason for reverting is: Revert due to crash..