Some transformations generate results we don't want to keep, so
let's disable such transformations for specific files.
Also, disable const-strlen.cocci everywhere, as the STRLEN macro has a
pretty limited scope, so the transformation generates false positives in
most cases.
With these additions, coccinelle finds everything fixed by the first
commit in PR #7695. In order not to needlessly conflict with that PR
this PR won't include those fixes, but only the coccinelle changes to
detect them automatically in the future.
