PPC: [runtime] Initial step towards switching Execution::Call to callable.

PPC: [runtime] Initial step towards switching Execution::Call to callable.

Port d5bbd45f044ae6796c0d0f7bd8732069d74418de

Original commit message:
    Currently Execution::Call (and friends) still duplicate a lot of the
    Call sequence logic that should be encapsulated in the Call and
    CallFunction builtins. So the plan now is to switch Execution::Call
    to accept any Callable and just pass that through to the Call builtin.

R=bmeurer@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, dstence@us.ibm.com
BUG=v8:4413
LOG=n

Committed: https://crrev.com/05c804fc1af8655595fe98deedd6bbc3a96f2973
Cr-Commit-Position: refs/heads/master@{#30813}

[MTBrandyberry, 2015-09-17 20:09:44]

The CQ bit was checked by mbrandy@us.ibm.com to run a CQ dry run

[commit-bot: I haz the power, 2015-09-17 20:09:59]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1347213003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1347213003/1

[michael_dawson, 2015-09-17 20:16:25]

On 2015/09/17 20:09:59, commit-bot: I haz the power wrote:
> Dry run: CQ is trying da patch. Follow status at
>  https://chromium-cq-status.appspot.com/patch-status/1347213003/1
> View timeline at
>  https://chromium-cq-status.appspot.com/patch-timeline/1347213003/1

lgtm

[commit-bot: I haz the power, 2015-09-17 20:35:12]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-17 20:35:13]

Dry run: This issue passed the CQ dry run.

[MTBrandyberry, 2015-09-17 20:38:07]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-09-17 20:38:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1347213003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1347213003/1

[commit-bot: I haz the power, 2015-09-17 20:39:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-17 20:40:15]

Patchset 1 (id:??) landed as
https://crrev.com/05c804fc1af8655595fe98deedd6bbc3a96f2973
Cr-Commit-Position: refs/heads/master@{#30813}