Move mtrack push and clear to separate functions

src/makemon.c

@@ -871,7 +871,7 @@ clone_mon(struct monst *mon,
     /* ms->isminion handled below */
 
     /* clone shouldn't be reluctant to move on spots 'parent' just moved on */
-    (void) memset((genericptr_t) m2->mtrack, 0, sizeof m2->mtrack);
+    mon_track_clear(m2);
 
     place_monster(m2, m2->mx, m2->my);
     if (emits_light(m2->data))