bug#21149: 25.0.50; Isearch with mixed case

[Glenn Morris]

Sebastien Vauban wrote:

> #+begin_src emacs-lisp
>   ;; use `w3m' browser (if installed) to render mails in HTML
>   (setq mm-text-html-renderer
>         (cond ((executable-find "w3m") 'w3m)
>               (t 'html2text)))          ; Emacs built-in
> #+end_src
> --8<---------------cut here---------------end--------------->8---
>
> Isearch only finds 1 occurrence, while there are 3 such strings
> (correctly reported by Anzu as well).

Works for me.
Please provide a minimal complete example starting from emacs -Q.
(Surely you know this by now?)