benchmark the poll-testing branch

<markusjm> Good morning. I was wondering if you had the free time to
run the maxscale performance test again on the poll-testing branch. I made some
changes to it after I found out that the design had a minor flaw. This change do
es mean that it needs some extra locking and I'm wondering how big of a performa
nce hit this is. The two commits that I'm interested in are 948c8d4e4841b6d53210
bf1566a03d1959049918 (current HEAD of poll-testing) and 3d4208ef3cb437fc085eba5
5058e04aaef6e7913 (the commit for the last benchmark). I'm mainly interested in
the 16 thread, single point select benchmark so I hope that lowers your workload
.