Fix bug in ARM instance field stores.

Fix bug in ARM instance field stores.

A large number of fields resulted in wrong offset
computation for the generated code for stores.

BUG=dartbug.com/19649
TEST=tests/language/large_class_declaration_test.dart
R=zra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37389

[zra, 2014-06-16 16:21:01]

lgtm

[zra, 2014-06-16 18:40:36]

On 2014/06/16 16:21:01, zra wrote:
> lgtm

It looks like the same problem exists on MIPS. Do you want to add the fix to
this CL? I can also take a look if that's easier.

[Florian Schneider, 2014-06-17 09:25:29]

On 2014/06/16 18:40:36, zra wrote:
> On 2014/06/16 16:21:01, zra wrote:
> > lgtm
> 
> It looks like the same problem exists on MIPS. Do you want to add the fix to
> this CL? I can also take a look if that's easier.

Oh - that may well be. Although, I did not see my test failing on MIPS: Do you
know which instructions (other than StoreInstanceField) could be affected?
I think I'll land this CL now, and you're welcome to look at the MIPS code,
since you probably have a better idea where problem could be there.

[Florian Schneider, 2014-06-17 09:28:34]

Committed patchset #1 manually as r37389 (presubmit successful).