Previous patch would not work for `multi-isearch-files'
because it is not checking `multi-isearch-file-list', so that
`multi-isearch-end' would be called.

We may replace
(if (and nopush edit multi-isearch-buffer-list)
with
(if (and nopush edit (or multi-isearch-buffer-list multi-isearch-file-list))
but just
(if (and nopush edit)
wold work in any situation and its shorter.