bug#25902: 25.1; yank mangles whitespace

[Eli Zaretskii]

> From: Norbert Kiesel <nkiesel@gmail.com>
> Date: Tue, 28 Feb 2017 12:48:01 -0800
> 
> since a couple of days I have a really annoying behavior in Emacs that a 
> `kill-line` followed by a `yank` often (but not always) does not 
> re-insert the whitespace of the killed line. This also happens when 
> running `emacs -Q`. Here is my test case 
> 
> 1. Start emacs using `emacs -Q` 
> 2. Switch to buffer `b.txt` [C-x b]
> 3. Insert the following text 
> 
> bla 
> first 
> second 
> third 
> 
> 4. Move cursor up to second line containing "first" (I use cursor keys for 
> that) 
> 5. Typing [C-k] followed by [C-y] results in 
> 
> bla 
> first second 
> third 

Not reproducible here.