vim-patch:8.1.2031: cursor position wrong when resizing and using conceal

Problem:    Cursor position wrong when resizing and using conceal.
Solution:   Set the flags that the cursor position is valid when setting the
            row and column during redrawing. (closes vim/vim#4931)
5babc6e858

src/nvim/screen.c

@@ -3868,6 +3868,7 @@ win_line (
       }
       wp->w_wrow = row;
       did_wcol = true;
+      curwin->w_valid |= VALID_WCOL|VALID_WROW|VALID_VIRTCOL;
     }
 
     // Don't override visual selection highlighting.