time-to-seconds related simplifications.

time-to-seconds related simplifications.

* lisp/gnus/gnus-util.el (with-no-warnings): Remove compat stub, now unused.
(gnus-float-time): On Emacs, always an alias.

* lisp/gnus/ecomplete.el (with-no-warnings): Remove compat stub, now unused.
(ecomplete-add-item): Use float-time on Emacs, else gnus-float-time.

* lisp/textmodes/remember.el (remember-time-to-seconds): Remove.
(remember-store-in-mailbox): Use float-time.

* lisp/calendar/timeclock.el (timeclock-time-to-seconds): Make it an alias.

* lisp/calendar/time-date.el (time-to-seconds): Always an alias on Emacs,
never a real function.
(with-no-warnings): Remove compat stub, now unused.
(time-less-p): Doc fix.
(time-to-number-of-days): Simplify.