fix a regression in Test

[ThomasBreuer]

After reporting a difference,
reset the line length to the previous value not to the default value.

resolves #5552

[fingolfin]

Fine by me. Would be good if @ChrisJefferson had another look, though.

[fingolfin]

Actually there is also PR #5549 which seems to be about the same issues, more or less, but a bit differently. (I asked @ChrisJefferson to review that, too, some time ago...). It would be good if you three (@ThomasBreuer @zickgraf @ChrisJefferson could figure out which way to go...)

[ThomasBreuer]

Thanks @fingolfin .
As far as I see, #5549 and #5553 do the same:

• There is a linelength before the tests, after the tests, and while printing differences. It is called size in Correctly restore screen size after printing diffs in tests #5549 and startsize in fix a regression in Test #5553.
• There is a linelength during the tests. It is called current_size in Correctly restore screen size after printing diffs in tests #5549 and size in fix a regression in Test #5553.
• There is a default linelength that is set at the beginning of the tests. It is called testsize in both cases. (This variable is used only once, we could also get rid of it.)

[zickgraf]

I also think that both PRs do the same. Since I was not fully convinced by the variable name current_size I used in #5549, I'm totally fine with using #5553 :-)

[ThomasBreuer]

Thanks @zickgraf.
I have now added a commit to remove the unnecessary local variable testsize; all we need is to set the linelength once before starting the tests, and later to switch between the linelengths outside the tests and inside the tests.
@ChrisJefferson ?

[ChrisJefferson]

Looks good to me, I'll just let the tests all cycle, then I'm happy to merge (or someone else can hit the button before me)