Fem3dMeshRenderTest, fix merge related compilation bug

- Update to new syntax for loading fems.
Merge branch 'fix/fem3d-loader-changes' into 'master'

Fix bug in fem3d mesh render test

+1: Julien Lenoir, Vien Tran, gsathyaseelan

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/789073