Refactor Object::SetSuperProperty and others.

Refactor Object::SetSuperProperty and others.

This is in preparation of implementing Reflect.set.

Besides making SetSuperProperty and others return Maybe<bool>, this CL
also fixes some parts of my previous refactoring of SetProperty and
others: It doesn't make sense to take both a language_mode and a
should_throw argument.  A strict language_mode should imply
THROW_ON_ERROR.

R=rossberg, verwaest@chromium.org
BUG=

Committed: https://crrev.com/127366112cb667fbe4a208d8c85121f9f23229a2
Cr-Commit-Position: refs/heads/master@{#31678}

[rossberg, 2015-10-29 16:43:57]

lgtm

[Toon Verwaest, 2015-10-30 09:32:18]

lgtm

[neis, 2015-10-30 09:47:50]

The CQ bit was checked by neis@chromium.org

[commit-bot: I haz the power, 2015-10-30 09:47:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1431443003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1431443003/1

[neis, 2015-10-30 09:48:05]

The CQ bit was unchecked by neis@chromium.org

[neis, 2015-10-30 10:08:36]

The CQ bit was checked by neis@chromium.org

[neis, 2015-10-30 10:08:36]

The patchset sent to the CQ was uploaded after l-g-t-m from
rossberg@chromium.org, verwaest@chromium.org
Link to the patchset: https://codereview.chromium.org/1431443003/#ps20001
(title: "Revert unintended change to test262 status file.")

[commit-bot: I haz the power, 2015-10-30 10:08:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1431443003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1431443003/20001

[commit-bot: I haz the power, 2015-10-30 10:45:41]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-30 10:46:21]

Patchset 2 (id:??) landed as
https://crrev.com/127366112cb667fbe4a208d8c85121f9f23229a2
Cr-Commit-Position: refs/heads/master@{#31678}