base1: Adjust test-http for recent playground change
base1: Adjust test-http for recent playground change

Commit 9afcaabd5c65 introduced a new playground page, which broke
test-http.html.

Closes #13924
deryni/cockpit,cockpituous/cockpit,cockpituous/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,garrett/cockpit,deryni/cockpit,garrett/cockpit,cockpit-project/cockpit,cockpituous/cockpit,mvollmer/cockpit,mvollmer/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,garrett/cockpit,garrett/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,garrett/cockpit,mvollmer/cockpit,martinpitt/cockpit,martinpitt/cockpit,martinpitt/cockpit,deryni/cockpit,cockpit-project/cockpit,cockpituous/cockpit,deryni/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpituous/cockpit,moraleslazaro/cockpit