Revert "Merge branch 'better_cpu_adjustement' into '1.6'"

This reverts merge request !1218 (merged)

the better_cpu_adjustment code is not stabilized, it produces at least one critical bug systematically (#1234 (closed)), so I propose to wait for this code to be stabilized before including it in a release, that's why I extract it from the 1.6 branch so that it doesn't be part of the next pre-release 1.6.15.

mentioned in commit 7d26a9b4

merged