use 'stop_option = end' as default restart write time

per https://github.com/COSIMA/access-om3/issues/175

Author: anton-seaice

ice_in

@@ -2,8 +2,7 @@
   bfbflag = "off" 
   conserv_check = .false.
   diagfreq = 960
-  dumpfreq = "y"
-  dump_last = .true.
+  dumpfreq = "x"
   histfreq = "d", "m", "x", "x", "x"
   hist_suffix = ".d", ".m", "x", "x", "x"
   hist_time_axis = "middle"

nuopc.runconfig

@@ -270,8 +270,8 @@ CLOCK_attributes::
      ice_cpl_dt = 99999 #not used
      lnd_cpl_dt = 99999 #not used
      ocn_cpl_dt = 3600 #ignored (coupling timestep set by nuopc.runseq) unless stop_option is nsteps
-     restart_n = 1
-     restart_option = nmonths
+     restart_n = -999
+     restart_option = end
      restart_ymd = -999
      rof_cpl_dt = 99999 #not used
      start_tod = 0