[dictionaries] Use IsKey(Isolate* i, Object* o) everywhere

[dictionaries] Use IsKey(Isolate* i, Object* o) everywhere

Using the isolate to check for IsUndefined and IsTheHole is roughly at least
20% faster in the worst-case and up to a factor 2x in the best case.

BUG=

Committed: https://crrev.com/764d4e6103404a18156f9916b277b999a43580f8
Cr-Commit-Position: refs/heads/master@{#36787}

[Camillo Bruni, 2016-06-07 08:48:41]

cbruni@chromium.org changed reviewers:
+ hpayer@chromium.org, yangguo@chromium.org

[Camillo Bruni, 2016-06-07 08:48:42]

Continuing my cleanup...

hpayer@ PTAL heap/.*
yangguo@ PTAL the rest

[Yang, 2016-06-07 10:49:39]

lgtm

[Hannes Payer (out of office), 2016-06-07 11:52:54]

lgtm

[Camillo Bruni, 2016-06-07 11:53:23]

The CQ bit was checked by cbruni@chromium.org

[commit-bot: I haz the power, 2016-06-07 11:53:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2031533002/60001

[commit-bot: I haz the power, 2016-06-07 12:22:02]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-06-07 12:22:54]

Description was changed from

==========
[dictionaries] Use IsKey(Isolate* i, Object* o) everywhere

Using the isolate to check for IsUndefined and IsTheHole is roughly at least
20% faster in the worst-case and up to a factor 2x in the best case.

BUG=
==========

to

==========
[dictionaries] Use IsKey(Isolate* i, Object* o) everywhere

Using the isolate to check for IsUndefined and IsTheHole is roughly at least
20% faster in the worst-case and up to a factor 2x in the best case.

BUG=

Committed: https://crrev.com/764d4e6103404a18156f9916b277b999a43580f8
Cr-Commit-Position: refs/heads/master@{#36787}
==========

[commit-bot: I haz the power, 2016-06-07 12:22:55]

Patchset 4 (id:??) landed as
https://crrev.com/764d4e6103404a18156f9916b277b999a43580f8
Cr-Commit-Position: refs/heads/master@{#36787}