Fix Observatory recompiles on fresh build

Fix Observatory recompiles on fresh build

- [x] GYPI: Remove buggy dependency on the sdk's packages.stamp which shouldn't have been a dependency in the first place.
- [x] GN: Switch output names to match new non-polymer based build

BUG=

Committed: https://github.com/dart-lang/sdk/commit/d78cbce63d0e7854accedaf7d700790ca1f4fb00

[Cutch, 2016-09-19 23:40:28]

Description was changed from

==========
Fix Observatory recompiles on fresh build

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

to

==========
Fix Observatory recompiles on fresh build

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

[Cutch, 2016-09-19 23:40:29]

johnmccutchan@google.com changed reviewers:
+ rmacnak@google.com

[Cutch, 2016-09-19 23:41:20]

Description was changed from

==========
Fix Observatory recompiles on fresh build

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

to

==========
Fix Observatory recompiles on fresh build

- [x] GYPI: Remove buggy dependency on the sdk's packages.stamp which shouldn't
have been a dependency in the first place.
- [x] GN: Switch output names to match new non-polymer based build

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

[Cutch, 2016-09-19 23:41:37]

TBR

[Cutch, 2016-09-19 23:41:47]

Description was changed from

==========
Fix Observatory recompiles on fresh build

- [x] GYPI: Remove buggy dependency on the sdk's packages.stamp which shouldn't
have been a dependency in the first place.
- [x] GN: Switch output names to match new non-polymer based build

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

to

==========
Fix Observatory recompiles on fresh build

- [x] GYPI: Remove buggy dependency on the sdk's packages.stamp which shouldn't
have been a dependency in the first place.
- [x] GN: Switch output names to match new non-polymer based build

BUG=

Committed:
https://github.com/dart-lang/sdk/commit/d78cbce63d0e7854accedaf7d700790ca1f4fb00
==========

[Cutch, 2016-09-19 23:41:48]

Committed patchset #1 (id:1) manually as
d78cbce63d0e7854accedaf7d700790ca1f4fb00 (presubmit successful).