Test reference files creation failed if Folder creation is needed.

[epernod]

If files have to be created for test : examples/toto/myAwsomeScene.scn
inside:
references/examples/toto
and toto folder doesn't exist, test failed:

[WriteState]:
    Message type   : Error
    Message content: Error creating compressed file C:/projects/sofa-src/applications/projects/Regression/references/examples/Components/solver/EulerExplicitSolver.scn.reference_0_mObject1_mstate.txt.gz
    source code loc: C:\projects\sofa-src\modules\SofaExporter\src\SofaExporter/WriteState.inl:103
      component: WriteState(unnamed)