This test takes 39 seconds on my machine even though it just runs
a couple of fakesrc num-buffers=2 ! fakesink pipelines. Most of
the cpu seems to be spent in libz, related to stack trace management.
Use stack-traces-flags=none instead of stack-traces-flags=full
until a better solution can be found. Might warrant more
investigation in any case..
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/503>