[utils] run_benchmarks: add test with one worker for bc-benchmark
[utils] run_benchmarks: highlight starting of benchmark
[utils] run_benchmarks: run daemon with 2 workers instead of 3

Seems faster, at least on next CPU's:
- Intel(R) Core(TM) i5-2310 CPU @ 2.90GHz (core i5 with 4 cores)
- Intel(R) Xeon(R) CPU E5-2620 0 @ 2.00GHz
[server] by default start with 2 workers. (see 992194c)