[turbofan] Introduce a Function type and optimize based on it.

[turbofan] Introduce a Function type and optimize based on it.

This inserts a new bit set type Function, which is used to represent
JSFunctions, and uses that type in typed lowering to optimize calls
to use the CallFunction builtin directly. Also allows for better typing
of the typeof operator, which can infern "function" for JSFunctions
properly.

R=jarin@chromium.org

Committed: https://crrev.com/dc3c84812a4583271338936ae78d70e5d8dbe228
Cr-Commit-Position: refs/heads/master@{#31827}

[Benedikt Meurer, 2015-11-05 12:42:02]

Hey Jaro,

As discussed earlier, the Function bitset type is back now (OKed with Andreas).
:-)
Please take a look.

Thanks,
Benedikt

[Jarin, 2015-11-05 12:48:59]

lgtm

[Benedikt Meurer, 2015-11-05 12:49:03]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-11-05 12:49:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1410343016/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1410343016/1

[Benedikt Meurer, 2015-11-05 12:59:32]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2015-11-05 12:59:32]

The patchset sent to the CQ was uploaded after l-g-t-m from jarin@chromium.org
Link to the patchset: https://codereview.chromium.org/1410343016/#ps20001
(title: "Undo unrelated change.")

[commit-bot: I haz the power, 2015-11-05 12:59:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1410343016/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1410343016/20001

[commit-bot: I haz the power, 2015-11-05 13:30:46]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-11-05 13:31:04]

Patchset 2 (id:??) landed as
https://crrev.com/dc3c84812a4583271338936ae78d70e5d8dbe228
Cr-Commit-Position: refs/heads/master@{#31827}