Remove pointer tests for ImageActor in vtkTextActor3D.
Remove pointer tests for ImageActor in vtkTextActor3D.

This ivar is always around, no need to test for it.

Change-Id: I1458d9bffef389b2d3aaf15b754aefc809eea375

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