Update tsuite to temper FLT_IS_DBL botches
Several sims in slow/ botch in all-double runs with the new default for the Fe+ model (Smyth+19). A botch in grid_extreme.in has migrated after Gargi Shaw's update of UMIST rates to 2012.
Reset the monitored values associated with these botches to the mean of the min/max values. Also, slightly widen error margins in a couple of occasions to allow for successful completion of sims across the entire test suite.