Hardening/harness errors under valgrind

### Description
Made the harness and valgrind tests a little easier on the eye.
Fixed a few errors in harness tests.

Not sure if we should leave this so open... I liked the previous way of explictely specifying the bytes number, as it makes the test more precise (ok, we would have some "false positive" fails at jenkins on the commits corresponding to steping in develop, but I think it is a small price to pay).