[turbofan] Add support for %_IsSpecObject intrinsic lowering.

[turbofan] Add support for %_IsSpecObject intrinsic lowering.

Now JSIntrinsicLowering can also lower %_IsSpecObject intrinsics to a
diamond.

R=mstarzinger@chromium.org

Committed: https://crrev.com/c55161bf167ffc2e0936d7316580a7bebd76ed76
Cr-Commit-Position: refs/heads/master@{#31960}

[Benedikt Meurer, 2015-11-12 13:33:32]

Hey Michi,

Another trivial %_ intrinsic that we want to keep.
Please take a look.

Thanks,
Benedikt

[Michael Starzinger, 2015-11-12 14:00:49]

LGTM.

[Benedikt Meurer, 2015-11-12 14:01:01]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-11-12 14:01:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1436943005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1436943005/1

[commit-bot: I haz the power, 2015-11-12 14:05:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-14 23:20:40]

Patchset 1 (id:??) landed as
https://crrev.com/c55161bf167ffc2e0936d7316580a7bebd76ed76
Cr-Commit-Position: refs/heads/master@{#31960}