Remove virtual/serviceworker test suite

It's no longer needed because --enable-service-worker has been removed.
This patch also removes passing expectation files for W3C harness tests,
no longer needed after https://codereview.chromium.org/328243002

BUG=365201

Review URL: https://codereview.chromium.org/345043002

git-svn-id: svn://svn.chromium.org/blink/trunk@176672 bbb929c8-8fbe-4397-9dbb-9b2b20218538