MIPS: [turbofan] Add new Float32Abs and Float64Abs operators.

MIPS: [turbofan] Add new Float32Abs and Float64Abs operators.

Port 9af9f1d0262e2dab66c62331a03f6a76504f3866

Original commit message:
These operators compute the absolute floating point value of some
arbitrary input, and are implemented without any branches (i.e. using
vabs on arm, and andps/andpd on x86).

BUG=

Committed: https://crrev.com/8c3af6ca03ffa8f61608614dc1c316d885a09801
Cr-Commit-Position: refs/heads/master@{#27679}

[balazs.kilvady, 2015-04-08 16:55:58]

balazs.kilvady@imgtec.com changed reviewers:
+ akos.palfi@imgtec.com, bmeurer@chromium.org, danno@chromium.org,
dusan.milosavljevic@imgtec.com, gergely.kis@imgtec.com, paul.lind@imgtec.com

[paul.l..., 2015-04-08 18:38:44]

LGTM. But missing mips64 unittests? You could add that here, or in a different
CL if you prefer.

[balazs.kilvady, 2015-04-08 18:58:17]

The CQ bit was checked by balazs.kilvady@imgtec.com

[balazs.kilvady, 2015-04-08 18:58:17]

The patchset sent to the CQ was uploaded after l-g-t-m from paul.lind@imgtec.com
Link to the patchset: https://codereview.chromium.org/1073463003/#ps20001
(title: "Add missing unittest.")

[commit-bot: I haz the power, 2015-04-08 18:58:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1073463003/20001

[commit-bot: I haz the power, 2015-04-08 19:30:11]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-08 19:30:25]

Patchset 2 (id:??) landed as
https://crrev.com/8c3af6ca03ffa8f61608614dc1c316d885a09801
Cr-Commit-Position: refs/heads/master@{#27679}