Upstream service worker indexedDB tests to WPT

The Web Platform Tests project includes a version that is roughly
equivalent, but it does not explicitly extend the lifetime of the
"message" event handler. Introduce this logic in the upstream version to
discourage worker termination.

Introduce additional improvements not previously implemented by either version:

- Schedule promise rejection in response to failed IndexedDB operations in
  order to improve reporting under failure conditions.
- Consistently destroy database following test execution

Remove the Chromium-specific version of this test.

BUG=688116
R=mek@chromium.org

Review-Url: https://codereview.chromium.org/2867573002
Cr-Commit-Position: refs/heads/master@{#476082}
5 files changed