Delete a bunch of packages that are now on GitHub.

pkg/scheduled_test/pubspec.yaml

-name: scheduled_test
-version: 0.11.6
-author: Dart Team <misc@dartlang.org>
-description: >
-  A package for writing readable tests of asynchronous behavior.
-
-  This package works by building up a queue of asynchronous tasks called a
-  "schedule", then executing those tasks in order. This allows the tests to
-  read like synchronous, linear code, despite executing asynchronously.
-
-homepage: http://www.dartlang.org
-environment:
-  sdk: '>=1.3.0 <2.0.0'
-dependencies:
-  http_multi_server: '>=1.0.0 <2.0.0'
-  http: '>=0.9.0 <0.12.0'
-  path: '>=0.9.0 <2.0.0'
-  shelf: '>=0.4.0 <0.6.0'
-  stack_trace: '>=0.9.1 <2.0.0'
-
-  # Because scheduled_test exports unittest, it needs to keep its version
-  # constraint tight to ensure that a constraint on scheduled_test properly
-  # constraints all features it provides.
-  unittest: '>=0.11.4 <0.11.5'
-dev_dependencies:
-  metatest: '>=0.1.0 <0.2.0'