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.
1 job for emacs-26 in 4 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
failed #338
test

00:00:04

 
Name Stage Failure
failed
test Test There has been a runner system failure, please try again
Running with gitlab-runner 11.4.2 (cf91d5e1)
on gitlab-runner-docker cff9d373
Using Docker executor with image debian:stretch ...
Pulling docker image debian:stretch ...
Using docker image sha256:4879790bd60d439cfe39c063660eef7af525d5f6f1cbb701a14c7cfc11cbfcf7 for debian:stretch ...
ERROR: Job failed (system failure): Error response from daemon: open /var/run/docker/libcontainerd/containerd/c59819d94833544ae527a6123ceaf67695770a1986cd46545f5aa0472836a75f/init/shim-log.json: no such file or directory (executor_docker.go:1015:1s)