vim-patch:9.0.0734: cursor position invalid when scrolling with 'smoothscroll'

Problem:    Cursor position invalid when scrolling with 'smoothscroll' set.
            (Ernie Rael)
Solution:   Add w_valid_skipcol and clear flags when it changes.  Adjust
            w_skipcol after moving the cursor.

2fbabd238a

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/normal.c

@@ -2566,6 +2566,8 @@ static bool nv_screengo(oparg_T *oap, int dir, long dist)
   if (atend) {
     curwin->w_curswant = MAXCOL;            // stick in the last column
   }
+  adjust_skipcol();
+
   return retval;
 }