patch 9.0.1428: cursor in wrong position when leaving insert mode

Problem:    Cursor in wrong position when leaving insert mode.
Solution:   Update the w_valid flags.  Position the cursor also when not
            redrawing. (closes #12137)

src/edit.c

@@ -3688,6 +3688,7 @@ ins_esc(
 	else
 	{
 	    --curwin->w_cursor.col;
+	    curwin->w_valid &= ~(VALID_WCOL|VALID_VIRTCOL);
 	    // Correct cursor for multi-byte character.
 	    if (has_mbyte)
 		mb_adjust_cursor();