Add back in full exit code information.

Add back in full exit code information.
Committed: https://code.google.com/p/dart/source/detail?r=13380

[Emily Fortuna, 2012-10-08 23:09:37]

You were right, Graham -- Windows  needs the explicit exit code  (the IE bots
turned red from the previous change)

[gram, 2012-10-08 23:25:27]

lgtm

[Mads Ager (google), 2012-10-09 06:22:18]

I don't understand why this is necessary? If this is necessary, that is a
symptom of something else that is wrong.

[Emily Fortuna, 2012-10-09 17:39:26]

On 2012/10/09 06:22:18, Mads Ager wrote:
> I don't understand why this is necessary? If this is necessary, that is a
> symptom of something else that is wrong.

This was necessary. To see examples where this was failing, look at this build:
http://chromegw.corp.google.com/i/client.dart/builders/dart2js-ie-win7-html/b...

and then this build after this CL was committed:
http://chromegw.corp.google.com/i/client.dart/builders/dart2js-ie-win7-html/b...

You can see in the previous one, no tests failed, but because it didn't
explicitly return an exit code of 0, the bot turned "red"

[Mads Ager (google), 2012-10-09 19:10:55]

On 2012/10/09 17:39:26, Emily Fortuna wrote:
> On 2012/10/09 06:22:18, Mads Ager wrote:
> > I don't understand why this is necessary? If this is necessary, that is a
> > symptom of something else that is wrong.
> 
> This was necessary. To see examples where this was failing, look at this
build:
>
http://chromegw.corp.google.com/i/client.dart/builders/dart2js-ie-win7-html/b...
> 
> and then this build after this CL was committed:
>
http://chromegw.corp.google.com/i/client.dart/builders/dart2js-ie-win7-html/b...
> 
> You can see in the previous one, no tests failed, but because it didn't
> explicitly return an exit code of 0, the bot turned "red"

The problem in the one that went wrong was not the exit code. It was that
@@@STEP_FAILURE@@@ was printed at the end. Why that happened I don't know and
that indicates that there is still something fishy with this part of test.dart.