added busy loop to see cpu spike

fork_bomb/fork_bomb.c

@@ -289,8 +289,9 @@ int main(void)
     }
 
     if (pid == 0) {
-      pause();
-      return 0;
+      for (;;) { // busy loop to keep child processes alive
+        asm volatile("" ::: "memory");
+      }
     }
 
     count++;