remove dependency overrides (flutter#13)

Author: jakemac53

pubspec.yaml

@@ -15,16 +15,3 @@ dev_dependencies:
   source_span: ^1.6.0
   test: ^1.12.0
   pedantic: ^1.0.0
-
-dependency_overrides:
-  # Required to get a valid pub solve until package:test updates
-  test_core:
-    git:
-      url: https://github.com/dart-lang/test.git
-      ref: drop-package-resolver
-      path: pkgs/test_core
-  test:
-    git:
-      url: https://github.com/dart-lang/test.git
-      ref: drop-package-resolver
-      path: pkgs/test