bug#44809: One very long line of <中文> XML tags puts emacs out of business

[積丹尼 Dan Jacobson]

1. Visit https://data.gov.tw/dataset/34315 .
2. Download e.g., B臺中市 .
3. Unzip, and open one of the more whopping XML files,

$ ls -ogS Downloads/B_XML/ | head -n 5
-rw-r--r-- 1 3091875 2020-04-13  b_4602.xml
-rw-r--r-- 1 3087978 2020-04-13  b_0755.xml
-rw-r--r-- 1 2874539 2020-04-13  b_5709.xml
-rw-r--r-- 1 2829385 2020-04-13  b_0530.xml

Press M-> [end-of-buffer]. Now press M-<.

You'll see the combination of one very long line, UTF-8 tags (<國有>),
etc. causes emacs to, well, only be able to process C-g's and beep.

Before long one can only put it out of its misery with
$ killall -1 emacs.
emacs-version "27.1"