Add --packages flag when compiling dart2js snapshot

Add --packages flag when compiling dart2js snapshot

BUG=
R=paulberry@google.com

Committed: https://github.com/dart-lang/sdk/commit/1f97819b25c593eebbea9dac535577bdbde796d8

[Bill Hesse, 2016-09-26 15:48:06]

whesse@google.com changed reviewers:
+ sigmund@google.com

[Bill Hesse, 2016-09-26 15:48:06]

The dart2js created in the SDK stopped working after CL
https://codereview.chromium.org/2372573002

You don't know any reason why dart2js should be compiled with different packages
than those that everything else uses, do you?  Or what the problem could be? 
Trying more of the same, as a fix.  Problem did not reproduce locally.

[Bill Hesse, 2016-09-26 16:33:58]

whesse@google.com changed reviewers:
+ paulberry@google.com, scheglov@google.com
- sigmund@google.com

[Bill Hesse, 2016-09-26 16:39:01]

On 2016/09/26 16:33:59, Bill Hesse wrote:

The issue on the buildbot seems to have resolved itself, but this CL should land
anyway, it fixes a potential build failure when there are stray .package files
in the checkout, which can be created by pub get or intellij.

[Paul Berry, 2016-09-26 16:45:43]

lgtm

[Bill Hesse, 2016-09-26 16:48:31]

Description was changed from

==========
Add --packages flag when compiling dart2js snapshot

BUG=
==========

to

==========
Add --packages flag when compiling dart2js snapshot

BUG=
R=paulberry@google.com

Committed:
https://github.com/dart-lang/sdk/commit/1f97819b25c593eebbea9dac535577bdbde796d8
==========

[Bill Hesse, 2016-09-26 16:48:33]

Committed patchset #1 (id:1) manually as
1f97819b25c593eebbea9dac535577bdbde796d8 (presubmit successful).

[scheglov, 2016-09-26 16:48:47]

lgtm

[Siggi Cherem (dart-lang), 2016-09-28 19:39:30]

sigmund@google.com changed reviewers:
+ sigmund@google.com

[Siggi Cherem (dart-lang), 2016-09-28 19:39:30]

lgtm