patch 8.2.2495: text jumps up and down when moving the cursor

Problem:    Text jumps up and down when moving the cursor in a small window
            with wrapping text and 'scrolloff' set.
Solution:   Adjust the computation of w_skipcol. (partly by Ghjuvan Lacambre,
            closes #7813)
diff --git a/src/testdir/test_breakindent.vim b/src/testdir/test_breakindent.vim
index 42b8c8c..98aff02 100644
--- a/src/testdir/test_breakindent.vim
+++ b/src/testdir/test_breakindent.vim
@@ -634,7 +634,7 @@
   call s:compare_lines(expect, lines)
   " Scroll down one screen line
   setl scrolloff=5
-  norm! 5gj
+  norm! 6gj
   redraw!
   let lines = s:screen_lines(1, 20)
   let expect = [