bug#38457: 27.0.50; dabbrev-expand regression due to message change

[Juri Linkov]

>>> > So please try to find a simpler fix for this problem, one that doesn't
>>> > involve a timer.
>>>
>>> This is the simplest and the safest solution.
>>
>> The simplest solution would be to prevent dabbrev-expand from
>> displaying the message in the first place; there are conditions for
>> that which evidently the new implementation somehow triggers.
>>
>>> I wanted to implement it earlier but had no time before.  I see no
>>> problems with it.
>>
>> Let's not rock the boat too much so close to the release cycle because
>> of a very minor problem which caused these changes.  You may not see
>> any problems with it now, but I'm certain we will bump into numerous
>> problems very soon if we make such significant changes in this
>> infrastructure, which is used everywhere in Emacs.
>
> Mmm, as you say, the message infrastructure is used everywhere in Emacs,
> and it has received significant changes in aa89c84e00d.
>
> I think the regression Stephen noticed is more widespread than just
> dabbrev-expand: e.g. TRAMP is also affected[1].

I know that TRAMP is affected.  I had no time to address this before, sorry,
but now this is fixed by the previous patch I sent 3 days ago that uses a timer.