Add a layout test for the case of failure by 404.

A 404 error from the remote server should cause the connection to fail
immediately. Verify that this works.

BUG=340568
TEST=run_webkit_tests.sh http/tests/websocket/handshake-fail-by-404.html

Review URL: https://codereview.chromium.org/153563002

git-svn-id: svn://svn.chromium.org/blink/trunk@166604 bbb929c8-8fbe-4397-9dbb-9b2b20218538