Remove dead test

This test uses an API in testRunner which Chromium never added.

I think this was a test for a WebKit API for Mail.app.

My changes to the preloader are about to make this test even more flaky.

BUG=356292

Review URL: https://codereview.chromium.org/355753003

git-svn-id: svn://svn.chromium.org/blink/trunk@176941 bbb929c8-8fbe-4397-9dbb-9b2b20218538