Something was changed in gcc 7->8 that made gcov report incorrect evaluation times for multi-line expression. Don't know what it was, don't care.
The numbers used in ac315e3e are not reproducible, used something close instead and re-computed reference
This follows up on 9dbf60e8
Test will not compile because they are still inprecise
(cherry picked from commit 7ad5f7a5)
This is currently disabled. There is no real point here, it's fast either way.