[runtime] Remove useless %_IsUndetectableObject intrinsic.

[runtime] Remove useless %_IsUndetectableObject intrinsic.

Instead of using a sequence

  if (something == null && !IS_UNDETECTABLE(something))) { ... }

which will be true if something is either null or undefined, it is
way simpler and way more efficient to just write

  if (something === null || something === (void 0)) { ... }

instead, which allows the compiler(s) to generate pretty decent code
without any need to resort to type feedback from a CompareNil IC.

R=yangguo@chromium.org

Committed: https://crrev.com/88f90680fd7357d1b561594b9e8592fbdc474946
Cr-Commit-Position: refs/heads/master@{#30135}

[Benedikt Meurer, 2015-08-12 13:13:39]

Hey Yang,

There's moar awesomeness w/ undetectable.
Please take a look.

Thanks,
Benedikt

Adam, Andreas, Dan: FYI

[Yang, 2015-08-12 13:15:59]

On 2015/08/12 13:13:39, Benedikt Meurer wrote:
> Hey Yang,
> 
> There's moar awesomeness w/ undetectable.
> Please take a look.
> 
> Thanks,
> Benedikt
> 
> Adam, Andreas, Dan: FYI

lgtm.

[Benedikt Meurer, 2015-08-12 13:18:34]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-08-12 13:18:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1288623003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1288623003/1

[commit-bot: I haz the power, 2015-08-12 13:44:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-12 13:44:29]

Patchset 1 (id:??) landed as
https://crrev.com/88f90680fd7357d1b561594b9e8592fbdc474946
Cr-Commit-Position: refs/heads/master@{#30135}