Add a LiveSuite class.

pubspec.yaml

 name: test
 version: 0.12.14-dev
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test
 environment:
   sdk: '>=1.13.0 <1.17.0'
 dependencies:
   analyzer: '>=0.23.0 <0.28.0'
   args: '^0.13.1'
   async: '^1.8.0'
   barback: '>=0.14.0 <0.16.0'
   boolean_selector: '^1.0.0'
-  collection: '^1.1.0'
+  collection: '^1.6.0'
   glob: '^1.0.0'
   http_multi_server: '>=1.0.0 <3.0.0'
   path: '^1.2.0'
   pool: '^1.2.0'
   pub_semver: '^1.0.0'
   shelf: '>=0.6.5 <0.8.0'
   shelf_static: '^0.2.0'
   shelf_web_socket: '^0.2.0'
   source_map_stack_trace: '^1.0.0'
   source_maps: '^0.10.1'
   source_span: '^1.0.0'
   stack_trace: '^1.2.1'
   stream_channel: '^1.3.1'
   string_scanner: '^0.1.1'
   web_socket_channel: '^1.0.0'
   yaml: '>=0.9.0 <3.0.0'
 
   # Use a tight version constraint to ensure that a constraint on matcher
   # properly constrains all features it provides.
   matcher: '>=0.12.0 <0.12.1'
 dev_dependencies:
   fake_async: '^0.1.2'
   scheduled_test: '^0.12.5'
+
+dependency_overrides:
+  collection: {path: ../collection}