Print test parameters like "foo: 123", and results like "foo = 123".

The way "latency average" was printed was differently if it was calculated
from the overall run time or was measured on a per-transaction basis.
Also, the per-script weight is a test parameter, rather than a result, so
use the "weight: %f" style for that.

Backpatch to 9.6, since the inconsistency on "latency average" was
introduced there.

Fabien Coelho

Discussion: <alpine.DEB.2.20.1607131015370.7486@sto>