TCK: Upgrade or replace HTMLUnit

[brideck]

There is a CVE that impacts the currently in-use 2.x version of HTMLUnit. In the 4.0 TCK, some work was done to provide an alternate Selenium implementation for portions where MyFaces' updated implementation was not compatible with the JS engine in HTMLUnit.

For future releases, either a non-HTMLUnit direction should be selected and migrated to or the HTMLUnit tests should be updated to use the new 3.x version. Some changes to test source would be needed to migrate to HTMLUnit 3.x.