Enable freetype tests when matplotlib is not found.
Enable freetype tests when matplotlib is not found.

Only a subset of the freetype tests also need mathtext, but all tests
were disabled when MPL wasn't found.

Change-Id: If19bb0249db5f9f0e256ead1357381aa85115006

gram526/VTK,mspark93/VTK,demarle/VTK,mspark93/VTK,sumedhasingla/VTK,candy7393/VTK,mspark93/VTK,jmerkow/VTK,keithroe/vtkoptix,jmerkow/VTK,mspark93/VTK,gram526/VTK,sankhesh/VTK,sumedhasingla/VTK,gram526/VTK,SimVascular/VTK,msmolens/VTK,mspark93/VTK,candy7393/VTK,sankhesh/VTK,sumedhasingla/VTK,candy7393/VTK,SimVascular/VTK,sankhesh/VTK,msmolens/VTK,demarle/VTK,gram526/VTK,candy7393/VTK,candy7393/VTK,sankhesh/VTK,sumedhasingla/VTK,sumedhasingla/VTK,sankhesh/VTK,demarle/VTK,gram526/VTK,sumedhasingla/VTK,candy7393/VTK,sumedhasingla/VTK,keithroe/vtkoptix,SimVascular/VTK,msmolens/VTK,SimVascular/VTK,SimVascular/VTK,mspark93/VTK,sumedhasingla/VTK,msmolens/VTK,keithroe/vtkoptix,jmerkow/VTK,jmerkow/VTK,candy7393/VTK,demarle/VTK,gram526/VTK,msmolens/VTK,keithroe/vtkoptix,jmerkow/VTK,demarle/VTK,mspark93/VTK,SimVascular/VTK,keithroe/vtkoptix,keithroe/vtkoptix,candy7393/VTK,jmerkow/VTK,msmolens/VTK,demarle/VTK,msmolens/VTK,gram526/VTK,msmolens/VTK,SimVascular/VTK,sankhesh/VTK,SimVascular/VTK,keithroe/vtkoptix,jmerkow/VTK,demarle/VTK,mspark93/VTK,sankhesh/VTK,demarle/VTK,jmerkow/VTK,keithroe/vtkoptix,gram526/VTK,sankhesh/VTK