Update unittest to new package layout.
Update unittest to new package layout.

Review URL: https://codereview.chromium.org//10917275

git-svn-id: 29b42837285a5fdcb6c8ad0409bff8538fc60ed2@12404 260f80e4-7a28-3924-810f-c04153c831b5

dart-lang/logging,astashov/logging