test: Enable tracer tests on rhel-8-4
test: Enable tracer tests on rhel-8-4

https://github.com/cockpit-project/bots/pull/1684 added python3-tracer
to the rhel-8-4 image.

martinpitt/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,garrett/cockpit,cockpit-project/cockpit,garrett/cockpit,martinpitt/cockpit,garrett/cockpit,garrett/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit