test: run some iterations of the stress test
test: run some iterations of the stress test

This commit ads some short iterations of stress testing to the malc
tests.

Very short messages counts are tested. The intent here is to test for
creation/destruction correctness which, given my experience, was the
trickiest thing to get right.

RafaGago/mini-async-log-c,RafaGago/mini-async-log-c,RafaGago/mini-async-log-c