Revert "Enable html/rendering."

This reverts commit dde0702a898147ef77b93e54f3664be2f5af12a2.
Revert "Update wptrunner and start running reftests."

This reverts commit 1d68ee689f26b9318e287a5db1f5c96d2a7905ce.

Fixes #4462.
auto merge of #4465 : servo/servo/revert-wpt, r=Ms2ger