Revert of JSObject::GetEnumProperty cleanup

Revert of JSObject::GetEnumProperty cleanup (patchset #2 id:20001 of https://codereview.chromium.org/1363293002/ )

Reason for revert:
Reverting, because of broken GC stress bots.

@cbruni: Sorry for the revert. I'm not entirely sure it's actually your CL; but policy is to revert speculatively if we can't determine an exact cause.

Original issue's description:
> JSObject::GetEnumProperty cleanup
>
> BUG=
>
> Committed: https://crrev.com/a00d47c802f93cf9835eafce4c9da2dd10b44f6a
> Cr-Commit-Position: refs/heads/master@{#30946}

TBR=jkummerow@chromium.org,cbruni@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/1213929ac3830e2fcf9ca72785d64f9e129b71e2
Cr-Commit-Position: refs/heads/master@{#30950}

[vogelheim, 2015-09-25 17:21:51]

Created Revert of JSObject::GetEnumProperty cleanup

[commit-bot: I haz the power, 2015-09-25 17:21:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1371673004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1371673004/1

[commit-bot: I haz the power, 2015-09-25 17:22:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-25 17:22:29]

Patchset 1 (id:??) landed as
https://crrev.com/1213929ac3830e2fcf9ca72785d64f9e129b71e2
Cr-Commit-Position: refs/heads/master@{#30950}

[Michael Achenbach, 2015-09-25 20:27:37]

All gc stress bots cycled green again after revert. Also auto-bisect pointed at
this CL, e.g.:
http://build.chromium.org/p/client.v8/builders/V8%20GC%20Stress%20-%202/build...