patch 9.1.1461: tabpanel: tabpanel vanishes with popup menu

Problem:  tabpanel: tabpanel vanishes with popup menu
Solution: remove pum-related test in tabpanel_leftcol(), refactor a few
          related functions (Hirohito Higashi)

This commit does the following:
- Delete unnecessary pum-related checks in the tabpanel_leftcol()
  function
- remove pum-related check in tabpanel_leftcol()
- The argument of the TPL_LCOL() macro has been deleted.
- The argument of the tabpanel_leftcol() function has been changed
  to void
- The return type of the `win_comp_pos()` function has been changed to
  void

closes: #17549

Signed-off-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/autocmd.c

@@ -1673,7 +1673,7 @@ aucmd_prepbuf(
 #endif
 
 	(void)win_split_ins(0, WSP_TOP | WSP_FORCE_ROOM, auc_win, 0, NULL);
-	(void)win_comp_pos();   // recompute window positions
+	win_comp_pos();   // recompute window positions
 	p_ea = save_ea;
 #ifdef FEAT_AUTOCHDIR
 	p_acd = save_acd;
@@ -1749,7 +1749,7 @@ win_found:
 	    close_tabpage(curtab);
 
 	restore_snapshot(SNAP_AUCMD_IDX, FALSE);
-	(void)win_comp_pos();   // recompute window positions
+	win_comp_pos();   // recompute window positions
 	unblock_autocmds();
 
 	save_curwin = win_find_by_id(aco->save_curwin_id);