Replace rest_index_ with has_rest_

Replace rest_index_ with has_rest_

rest_index_ is implicitly params_.length() - 1, since it can only be the last.
Add dchecks that no parameters are added after the rest parameter.

BUG=v8:5209
Committed: https://crrev.com/6e4d678db9aa9fe355cb6948a1f0d51451e3acc6
Cr-Commit-Position: refs/heads/master@{#38858}

[Toon Verwaest, 2016-08-24 05:10:55]

verwaest@chromium.org changed reviewers:
+ neis@chromium.org

[Toon Verwaest, 2016-08-24 05:10:56]

ptal, the change you suggested.

[neis, 2016-08-24 08:28:03]

On 2016/08/24 05:10:56, Toon Verwaest wrote:
> ptal, the change you suggested.

Thanks!

Can you now also make the following changes?
- Remove rest_parameter(int* index), as the index seems to be unused (see
AstGraphBuilder::BuildRestArgumentsArray).
- Instead, use has_rest_parameter() + rest_parameter() in ignition, full-codegen
(only x64???), hydrogen, and turbofan.
- Use only has_rest_parameter() in ast-numbering.

[Toon Verwaest, 2016-08-24 08:39:43]

Let's do it in a follow-up?

[neis, 2016-08-24 08:41:16]

On 2016/08/24 08:39:43, Toon Verwaest wrote:
> Let's do it in a follow-up?

ok

[neis, 2016-08-24 08:41:21]

lgtm

[Toon Verwaest, 2016-08-24 08:44:58]

The CQ bit was checked by verwaest@chromium.org

[commit-bot: I haz the power, 2016-08-24 08:45:08]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-24 09:15:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-24 09:15:28]

Description was changed from

==========
Replace rest_index_ with has_rest_

rest_index_ is implicitly params_.length() - 1, since it can only be the last.
Add dchecks that no parameters are added after the rest parameter.

BUG=v8:5209
==========

to

==========
Replace rest_index_ with has_rest_

rest_index_ is implicitly params_.length() - 1, since it can only be the last.
Add dchecks that no parameters are added after the rest parameter.

BUG=v8:5209

Committed: https://crrev.com/6e4d678db9aa9fe355cb6948a1f0d51451e3acc6
Cr-Commit-Position: refs/heads/master@{#38858}
==========

[commit-bot: I haz the power, 2016-08-24 09:15:30]

Patchset 1 (id:??) landed as
https://crrev.com/6e4d678db9aa9fe355cb6948a1f0d51451e3acc6
Cr-Commit-Position: refs/heads/master@{#38858}