429168: fix for PdfJs regression

Fix for bug 429168, PdfJs regression. We pay a very high cost for AllocationResult being a > kPointerSize struct. This can be avoided by using Smis to indicate failure with retry spaces.

BUG=429168
LOG=N
R=yangguo@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=25057

[mvstanton, 2014-11-01 15:33:35]

mvstanton@chromium.org changed reviewers:
+ yangguo@chromium.org

[mvstanton, 2014-11-01 15:34:24]

Hi Yang,
I carried out your idea of using Smi to encode failure with a retry space. Works
absolutely great! PTAL, thanks,
--Michael

[Yang, 2014-11-03 08:04:52]

On 2014/11/01 15:34:24, mvstanton wrote:
> Hi Yang,
> I carried out your idea of using Smi to encode failure with a retry space.
Works
> absolutely great! PTAL, thanks,
> --Michael

lgtm.

[mvstanton, 2014-11-03 08:43:32]

Committed patchset #1 (id:1) manually as 25057 (presubmit successful).