export/import IFC specific parameter is lost

Hello
sea [IFC2REVIT en perd des bouts.pdf](https://github.com/Autodesk/revit-ifc/files/2402168/IFC2REVIT.en.perd.des.bouts.pdf)
1. Make a very simple model : 4 walls 1 space
2. Create a specific parameter for objects space (IfcSpace)
3. Put a value of test for the space create here
4. Export it in IFC
5. Check that the parameter was well recorded in the IFC with a notepad or a IFC viewer
6. Open the model IFC with REVIT and see if the space guards its parameter ... the parameter is lost :c

Reproduce the reported workflow with a four-wall, one-space model: create a specific parameter on the IfcSpace, export to IFC, and inspect it in a text editor or IFC viewer before reopening it in Revit. Trace the IFC export/import handling for IfcSpace parameters; done means the parameter value survives the round trip. No source files or tests are named, so begin by locating the relevant export and import entry points.

Written by the indexing model from the issue text.