test: move test-http-dump-req-when-res-end

The implementataion is sensitive to system resource availability, so
move it to sequential instead of running out of parallel directory.

Fixes: #19139

PR-URL: #19819
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: Trott