Move cyclic tests to fns-tests.el

Move cyclic tests to fns-tests.el

* test/src/fns-tests.el (cyc1, cyc2, dot1, dot2): New functions.
(test-cycle-length, test-cycle-safe-length, test-cycle-member)
(test-cycle-memq, test-cycle-memql, test-cycle-assq)
(test-cycle-assoc, test-cycle-rassq, test-cycle-rassoc)
(test-cycle-delq, test-cycle-delete, test-cycle-reverse)
(test-cycle-plist-get, test-cycle-lax-plist-get)
(test-cycle-plist-member, test-cycle-plist-put)
(test-cycle-lax-plist-put, test-cycle-equal, test-cycle-nconc):
New tests.
* test/manual/cyclic-tests.el: File deleted.