testing: Use vtk-example as a fallback for prefix
testing: Use vtk-example as a fallback for prefix

Change-Id: I627bdd7ae131a3eff1b2e08a9b709760af178c28

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