ServiceWorker: Registering a malformed script should fail [3/3]

Before this series of patches, registration succeeds even if the worker script
has a syntax error because the installing sequence does not check the result of
the script evaluation.

This adds layout tests for a variety of error cases.

Patch dependency:
[1] Blink: https://codereview.chromium.org/692003002/
[2] Chromium: https://codereview.chromium.org/697593002/
[3] Blink: THIS PATCH

BUG=426344
TEST=run-webkit-tests --debug http/tests/serviceworker/

Review URL: https://codereview.chromium.org/697833004

git-svn-id: svn://svn.chromium.org/blink/trunk@184903 bbb929c8-8fbe-4397-9dbb-9b2b20218538