Fix the 'shouldThrowException()' implementation in http/tests/security.

This method had a typo, which means that it never actually worked. It threw
an exception based on the non-existent 'e' variable, and didn't write out
the exception type, which masked the error.

This patch fixes the typo, adds the exception text, and rebaselines the 4
effected tests.

Ideally, we'd rewrite all these tests with 'js-test-pre.js', but I don't
see myself doing that right this moment. :)

R=jochen@chromium.org

Review URL: https://chromiumcodereview.appspot.com/25010002

git-svn-id: svn://svn.chromium.org/blink/trunk@158435 bbb929c8-8fbe-4397-9dbb-9b2b20218538