fix valgrind error in vtkTreeHeatmapItem tests
fix valgrind error in vtkTreeHeatmapItem tests

The use of MultiplyPoint() on a double[3] was causing the
following valgrind error to occur:

Conditional jump or move depends on uninitialised value(s)

Change-Id: I37cdb1ae0a3a7682005ff5e04bdf050f1c70dfae

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