bug#36032: 27.0.50; Massive GC when shift-selecting text in HELLO

[martin rudalics]

>> When with emacs -Q --load "~/show-gc.el" I'm at the beginning of
>>
>> Dutch (Nederlands)
>>
>> doing C-SPC and then C-f until I'm at the end of that text I get 19
>> additional collection cycles.
>
> I get 17 for the first C-f at the beginning of the buffer, and then
> just one more for the Dutch line.
>
> But neither the 17 first GCs nor the 18th one cause any tangible
> delays in response to C-f.

Interesting.  Here the release branch is just as slow as master.
Visiting HELLO takes about 50 seconds and one shifted C-f about one
second (or one GC cycle) regardless of where in the buffer I am.
Moreover, -O0 and -O3 builds incur about the same delays.

martin