bug#56815: 29.0.50; Isearch lazy-highlight highlights too much when truncate-lines is in effect

[Juri Linkov]

>>> >>   (or truncate-lines (truncated-partial-width-window-p))
>>> >
>>> > Fine by me.
>>> 
>>> Then I'll push a better patch:
>>
>> Btw, I didn't use window-total-width instead of window-width.  What I
>> did mimics what the display engine does when it determines whether to
>> truncate lines in a window.  So I think
>> truncated-partial-width-window-p should be fixed to use
>> window-total-width instead.
>
> Now this patch fixes truncated-partial-width-window-p to use
> window-total-width.  Also it fixes the recent code for
> long_line_optimizations_p in scan_for_column to better mimic
> what the display engine does:

Now pushed to master.