fails:Float#to_s uses e format for a positive value with whole part having 18 significant figures
fails:Float#to_s uses e format for a negative value with whole part having 18 significant figures
fails:Float#to_s uses non-e format for a positive value with whole part having 17 significant figures
fails:Float#to_s uses non-e format for a negative value with whole part having 17 significant figures
