Merge #2545: Fix clang analysis warnings. (12)

Reviewed-by: oni-link <knil.ino@gmail.com>

src/nvim/ex_cmds2.c

@@ -1897,6 +1897,7 @@ void ex_listdo(exarg_T *eap)
         /* go to window "wp" */
         if (!win_valid(wp))
           break;
+        assert(wp);
         win_goto(wp);
         if (curwin != wp)
           break;            /* something must be wrong */
@@ -1905,6 +1906,7 @@ void ex_listdo(exarg_T *eap)
         /* go to window "tp" */
         if (!valid_tabpage(tp))
           break;
+        assert(tp);
         goto_tabpage_tp(tp, TRUE, TRUE);
         tp = tp->tp_next;
       } else if (eap->cmdidx == CMD_bufdo) {

src/nvim/ex_docmd.c

@@ -5813,6 +5813,7 @@ static void ex_tabonly(exarg_T *eap)
           break;
         }
       }
+      assert(first_tabpage);
       if (first_tabpage->tp_next == NULL) {
         break;
       }