jwg12 Add IfcStrippedOptional

[aothms]

Compatibility with IFC4 ISO version (and to be used for referencing deleted schema types)

[aothms]

--- tmp/a/IFC.exp	2022-08-27 01:14:51.982286600 +0200
+++ tmp/b/IFC.exp	2022-09-05 20:19:15.809952400 +0200
@@ -357,20 +357,23 @@
 END_TYPE;
 
 TYPE IfcSpecularExponent = REAL;
 END_TYPE;
 
 TYPE IfcSpecularRoughness = REAL;
  WHERE
 	 WR1 : {0.0 <= SELF <= 1.0};
 END_TYPE;
 
+TYPE IfcStrippedOptional = BOOLEAN;
+END_TYPE;
+
 TYPE IfcTemperatureGradientMeasure = REAL;
 END_TYPE;
 
 TYPE IfcTemperatureRateOfChangeMeasure = REAL;
 END_TYPE;
 
 TYPE IfcText = STRING;
 END_TYPE;
 
 TYPE IfcTextAlignment = STRING;