The FreeTypeTextMapper tests used to strip out object factories
that provided vtkTextMapper overrides. This prevented the (now
removed) vtkRenderingFreeTypeOpenGL module from hiding the
improved generic implementation in vtkTextMapper, which is what
the tests where exercising.

Now that vtkRenderingOpenGL2 overrides vtkTextMapper to provide
GL2PS export extensions, this code is breaking the tests by
removing all OpenGL2-specific classes from the object factory.

The offending outdated code has been removed.