revision: "simplify" options imply topo-order sort

The code internally runs sort_in_topo_order() already; it is more clear
to spell it out in the option parsing phase, instead of adding a special
case in simplify_merges() function.

revision.c

@@ -1358,11 +1358,13 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->topo_order = 1;
 	} else if (!strcmp(arg, "--simplify-merges")) {
 		revs->simplify_merges = 1;
+		revs->topo_order = 1;
 		revs->rewrite_parents = 1;
 		revs->simplify_history = 0;
 		revs->limited = 1;
 	} else if (!strcmp(arg, "--simplify-by-decoration")) {
 		revs->simplify_merges = 1;
+		revs->topo_order = 1;
 		revs->rewrite_parents = 1;
 		revs->simplify_history = 0;
 		revs->simplify_by_decoration = 1;
@@ -2016,8 +2018,6 @@ static void simplify_merges(struct rev_info *revs)
 	struct commit_list *list;
 	struct commit_list *yet_to_do, **tail;
 
-	if (!revs->topo_order)
-		sort_in_topological_order(&revs->commits, revs->lifo);
 	if (!revs->prune)
 		return;