[Groff] pic bug between 1.18.1 and 1.19.x

[Zvezdan Petkovic]

Pic bug that started in 1.19.x series is still not fixed.

Gpresent .PAUSE request, in combination with pic for loop, triggers a
vertical move which screws up a picture.
See the attached file for the example pic code.
Make a picture.  Then
add
        .copy "animate.pic"
after .PS
and instead of every, line, circle, etc., call

        animate(red, blue, line down from X to Y)

Run it through gpresent and see your picture destroyed.
The animate macro worked fine in 1.18.x.

I have other examples of this bug, but this should be enough to
reproduce the problem.

        ZP

animate.pic
Description: Text document