Only test osimC3D if WITH_C3D.
Only test osimC3D if WITH_C3D.

[ci skip] [skip ci]

opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core