Remove spurious node duplicate suppression, doesn't work, not wanted.
(info-xref-output): Take format style args, add "sit-for 0" to let
user see the results as they progress.
(info-xref-check-all-custom): New function.
(info-xref-all-info-files): Cons a bit less.
(info-xref-check-buffer): Use push and replace-regexp-in-string.
(info-xref-output): Call insert only once.
(info-xref-whitespace): Remove.
