Exclude failing Selenium 2 tests on IE8 from running

This is one of the final steps in preparing our build to be tested on Internet Explorer 8.

Because this is the first time we try running tests on Windows or on IE8, a lot of tests fail because of several reasons. So in order to avoid a build failure or getting spammed by the Jenkins master each time a build fails, the goal is to skip the failing tests for the moment so we can start a Jenkins agent on Windows + IE8.
After we do this, we can start fixing tests individually and re-enable the tests.