patch 8.1.0856: when scrolling a window the cursorline is not always updated

patch 8.1.0856: when scrolling a window the cursorline is not always updated

Problem:    When scrolling a window other than the current one the cursorline
            highlighting is not always updated. (Jason Franklin)
Solution:   Call redraw_for_cursorline() after scrolling.  Only set
            w_last_cursorline when drawing the cursor line.  Reset the lines
            to be redrawn also when redrawing the whole window.