tests: leak tracer: disable stack traces for faster test execution
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 cycles seems to be spent in libz, related to stack trace management presumably.
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 though, something seems very very wrong here?