Fix zone usage within LAllocator.

Fix zone usage within LAllocator.
    
Previously all allocations in the register allocator were done on the
chunk (and graph) zone, even those that did not need to survive past
the register allocation. Now only allocations that need to survive
use the chunk zone, all other allocations use a separate zone local
to the LAllocator.
    
Depends on https://codereview.chromium.org/18022002

R=danno@chromium.org
BUG=

Committed: https://code.google.com/p/v8/source/detail?r=15372

[danno, 2013-06-27 13:42:22]

Shouldn't you make this an LPhase before going through all the trouble of
converting the zone usage?

[Benedikt Meurer, 2013-06-27 19:55:12]

On 2013/06/27 13:42:22, danno wrote:
> Shouldn't you make this an LPhase before going through all the trouble of
> converting the zone usage?

The whole chunk construction, including the register allocation?

[danno, 2013-06-27 20:57:49]

Looking at this again, it seems just fine. I think I missed  where the zones
were coming from in the first round. lgtm.

[Benedikt Meurer, 2013-06-28 07:37:08]

Committed patchset #2 manually as r15372 (presubmit successful).