cl-make-random-state was not copying its arg

Problem reported by Xu Chunyang (Bug#33731).
* lisp/emacs-lisp/cl-extra.el (cl-make-random-state):
Use copy-sequence, not copy-tree, so that the record is copied.
* test/lisp/emacs-lisp/cl-extra-tests.el:
(cl-extra-test-cl-make-random-state): New test.

lisp/emacs-lisp/cl-extra.el

@@ -484,7 +484,7 @@ Optional second arg STATE is a random-state object."
 If STATE is t, return a new state object seeded from the time of day."
   (unless state (setq state cl--random-state))
   (if (cl-random-state-p state)
-      (copy-tree state t)
+      (copy-sequence state)
     (cl--make-random-state (if (integerp state) state (cl--random-time)))))
 
 ;; Implementation limits.

test/lisp/emacs-lisp/cl-extra-tests.el

@@ -94,4 +94,9 @@
     (should (equal (list lst3 (cdr lst3) (cddr lst3))
                    (cl-maplist fn3 lst lst2 lst3)))))
 
+(ert-deftest cl-extra-test-cl-make-random-state ()
+  (let ((s (cl-make-random-state)))
+    ;; Test for Bug#33731.
+    (should-not (eq s (cl-make-random-state s)))))
+
 ;;; cl-extra-tests.el ends here