PPC: [turbofan] Introduce optional Float64Min and Float64Max machine operators.

PPC: [turbofan] Introduce optional Float64Min and Float64Max machine operators.

Port 99f8d57f3c5d967bc3b10356b22d7ec7be55e89f

Original commit message:
Basically recognize certain x < y ? x : y constructs and turn that into
Float64Min/Float64Max operations, if the target machine supports that.
On x86 we lower to (v)minsd/(v)maxsd.

R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/998283002

Cr-Commit-Position: refs/heads/master@{#27160}

R=danno@chromium.org, svenpanne@chromium.org

BUG=

Committed: https://crrev.com/0697e929529b9467f6f5fe04509d57ff8e22c098
Cr-Commit-Position: refs/heads/master@{#27174}

[michael_dawson, 2015-03-12 19:15:14]

PPC Fix for next breaking change.

[michael_dawson, 2015-03-12 19:21:20]

On 2015/03/12 19:15:14, michael_dawson wrote:
> PPC Fix for next breaking change.

I'll have to wait until this gets in before I can submit the next one which
leverages it.

[dcarney, 2015-03-12 19:34:10]

lgtm

[Sven Panne, 2015-03-13 07:20:46]

The CQ bit was checked by svenpanne@chromium.org

[commit-bot: I haz the power, 2015-03-13 07:21:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1005693002/1

[commit-bot: I haz the power, 2015-03-13 07:39:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-13 07:40:16]

Patchset 1 (id:??) landed as
https://crrev.com/0697e929529b9467f6f5fe04509d57ff8e22c098
Cr-Commit-Position: refs/heads/master@{#27174}