fix infovis tests
fix infovis tests

Tests segfault when vtkTextMapper::New() returned a NULL pointer.

vtkTextMapper it turns out is an interface class for which
vtkOpenGLFreeTypeTextMapper is, for now, the only implementation. There could
be other implementations, so making a hard module dependency which cmake would
resolve automatically isn't the right solution. Instead, unfortunately you
have to manually provide a dependency to Rendering/FreeTypeOpenGL.

Change-Id: I0cf1e81bd14e226d09df07b2fcddae3f3df1404e

demarle/VTK,gram526/VTK,keithroe/vtkoptix,candy7393/VTK,collects/VTK,ashray/VTK-EVM,SimVascular/VTK,jmerkow/VTK,johnkit/vtk-dev,demarle/VTK,sankhesh/VTK,keithroe/vtkoptix,johnkit/vtk-dev,aashish24/VTK-old,keithroe/vtkoptix,berendkleinhaneveld/VTK,collects/VTK,gram526/VTK,sumedhasingla/VTK,SimVascular/VTK,collects/VTK,msmolens/VTK,ashray/VTK-EVM,hendradarwin/VTK,hendradarwin/VTK,aashish24/VTK-old,SimVascular/VTK,berendkleinhaneveld/VTK,hendradarwin/VTK,sumedhasingla/VTK,SimVascular/VTK,ashray/VTK-EVM,sankhesh/VTK,jmerkow/VTK,mspark93/VTK,ashray/VTK-EVM,jmerkow/VTK,demarle/VTK,collects/VTK,msmolens/VTK,sankhesh/VTK,gram526/VTK,candy7393/VTK,msmolens/VTK,mspark93/VTK,msmolens/VTK,aashish24/VTK-old,keithroe/vtkoptix,msmolens/VTK,jmerkow/VTK,biddisco/VTK,sumedhasingla/VTK,hendradarwin/VTK,keithroe/vtkoptix,hendradarwin/VTK,keithroe/vtkoptix,berendkleinhaneveld/VTK,hendradarwin/VTK,sankhesh/VTK,SimVascular/VTK,sumedhasingla/VTK,mspark93/VTK,biddisco/VTK,aashish24/VTK-old,johnkit/vtk-dev,candy7393/VTK,sumedhasingla/VTK,demarle/VTK,gram526/VTK,gram526/VTK,collects/VTK,mspark93/VTK,johnkit/vtk-dev,ashray/VTK-EVM,demarle/VTK,ashray/VTK-EVM,johnkit/vtk-dev,gram526/VTK,demarle/VTK,SimVascular/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,mspark93/VTK,jmerkow/VTK,aashish24/VTK-old,sankhesh/VTK,candy7393/VTK,johnkit/vtk-dev,keithroe/vtkoptix,berendkleinhaneveld/VTK,candy7393/VTK,candy7393/VTK,mspark93/VTK,ashray/VTK-EVM,mspark93/VTK,berendkleinhaneveld/VTK,msmolens/VTK,aashish24/VTK-old,biddisco/VTK,jmerkow/VTK,sumedhasingla/VTK,SimVascular/VTK,mspark93/VTK,biddisco/VTK,demarle/VTK,jmerkow/VTK,candy7393/VTK,keithroe/vtkoptix,johnkit/vtk-dev,biddisco/VTK,hendradarwin/VTK,jmerkow/VTK,candy7393/VTK,gram526/VTK,collects/VTK,berendkleinhaneveld/VTK,sankhesh/VTK,sankhesh/VTK,biddisco/VTK,ashray/VTK-EVM,SimVascular/VTK,biddisco/VTK,msmolens/VTK,msmolens/VTK,sankhesh/VTK,sumedhasingla/VTK,gram526/VTK,demarle/VTK