Revert "tests: Install full chromium and Xvfb"
Revert "tests: Install full chromium and Xvfb"

This reverts commit cc7bdae247e30a2d0838e63c9e7af5fb7ab8bc52.

We don't need this any more in Cockpit, see
<https://github.com/cockpit-project/cockpit/pull/9542>.

cockpit-project/cockpituous,cockpit-project/cockpituous