patch 8.2.3297: cannot use all commands inside a {} block

Problem:    Cannot use all commands inside a {} block after :command and
            :autocmd.
Solution:   Do consider \n to separate commands. (closes #8620)
diff --git a/src/eval.c b/src/eval.c
index 550fe8e..a72519d 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2314,7 +2314,7 @@
     }
 
     if (eap != NULL)
-	eap->nextcmd = check_nextcmd(p);
+	set_nextcmd(eap, p);
 
     return ret;
 }
@@ -6173,7 +6173,7 @@
 	clear_tv(&rettv);
 	arg = skipwhite(arg);
     }
-    eap->nextcmd = check_nextcmd(arg);
+    set_nextcmd(eap, arg);
     clear_evalarg(&evalarg, eap);
 
     if (eap->skip)
@@ -6317,7 +6317,7 @@
     if (eap->skip)
 	--emsg_skip;
 
-    eap->nextcmd = check_nextcmd(arg);
+    set_nextcmd(eap, arg);
 }
 
 /*