bug#54904: list timers showing unnecessary verbose time info

[Kiss Dénes]

E.g:


                3m 42.7s       5m 0.0s savehist-autosave
                5m 44.2s    1h 0m 0.0s url-cookie-write-file
            8h 14m 27.1s 1d 0h 0m 0.0s clean-buffer-list
           11h 14m 27.4s 1d 0h 0m 0.0s run-hooks
           18h 34m 27.1s 1d 0h 0m 0.0s recentf-cleanup

The 0s should be dropped from the end, so the time column gets less busy, more 
readable, so

5m 0.0s       should be just 5m
1h 0m 0.0s    should be just 1h
1d 0h 0m 0.0s should be just 1d

etc.