:l_flag:: be more aggressive when normalizing whitespace

Save output from ls -ldT and stat -l, then normalize all repeating whitespace using
sed to single column spaces.

This makes the test flexible with single-digit days, etc, similar to r320723. This
approach is just a bit more of a hammer approach because of how the columns are
ordered/spaced in both ls and stat.

MFC after: 1 week
MFC with: r319841