bug#39658: 26.3; can't edit file with terminal escape sequences

[Robert Pluim]

>>>>> On Tue, 18 Feb 2020 05:48:59 -0800, frederik@ofb.net said:

    frederik> To reproduce, open the attached file in Emacs, and type C-x C-n. 
On my system Emacs uses 100% of CPU, indefinitely.
    frederik> I can open the file in Vim (where it only lets me see the first 
part of the line) and in Gedit.

    frederik> The file came from debugging Neomutt's use of curses. Thanks.

The problem is more likely to be the extremely long lines in the
file. If you have emacs-27 or emacs-master, you can try 'M-x
global-so-long-mode' before visiting the file, which attempts to
improve Emacs' behaviour in such cases.

Robert