ENH: Minor improvements
ENH: Minor improvements

Added barrier synchronization after each subtest
and resolved misc. issues with using the
vtkXMLHierarchicalBoxWriter.

cjh1/VTK,keithroe/vtkoptix,msmolens/VTK,demarle/VTK,sankhesh/VTK,cjh1/VTK,aashish24/VTK-old,sumedhasingla/VTK,collects/VTK,collects/VTK,sankhesh/VTK,biddisco/VTK,gram526/VTK,SimVascular/VTK,SimVascular/VTK,biddisco/VTK,demarle/VTK,sumedhasingla/VTK,aashish24/VTK-old,msmolens/VTK,jmerkow/VTK,johnkit/vtk-dev,candy7393/VTK,hendradarwin/VTK,berendkleinhaneveld/VTK,msmolens/VTK,keithroe/vtkoptix,keithroe/vtkoptix,aashish24/VTK-old,keithroe/vtkoptix,johnkit/vtk-dev,biddisco/VTK,johnkit/vtk-dev,candy7393/VTK,biddisco/VTK,collects/VTK,cjh1/VTK,ashray/VTK-EVM,gram526/VTK,sankhesh/VTK,aashish24/VTK-old,mspark93/VTK,jmerkow/VTK,candy7393/VTK,berendkleinhaneveld/VTK,sankhesh/VTK,berendkleinhaneveld/VTK,demarle/VTK,keithroe/vtkoptix,sumedhasingla/VTK,ashray/VTK-EVM,berendkleinhaneveld/VTK,msmolens/VTK,aashish24/VTK-old,keithroe/vtkoptix,SimVascular/VTK,keithroe/vtkoptix,mspark93/VTK,mspark93/VTK,hendradarwin/VTK,sankhesh/VTK,msmolens/VTK,demarle/VTK,biddisco/VTK,johnkit/vtk-dev,cjh1/VTK,candy7393/VTK,gram526/VTK,SimVascular/VTK,jmerkow/VTK,candy7393/VTK,hendradarwin/VTK,ashray/VTK-EVM,sumedhasingla/VTK,SimVascular/VTK,johnkit/vtk-dev,biddisco/VTK,johnkit/vtk-dev,gram526/VTK,SimVascular/VTK,mspark93/VTK,SimVascular/VTK,johnkit/vtk-dev,jmerkow/VTK,gram526/VTK,hendradarwin/VTK,cjh1/VTK,berendkleinhaneveld/VTK,msmolens/VTK,mspark93/VTK,demarle/VTK,demarle/VTK,collects/VTK,msmolens/VTK,mspark93/VTK,jmerkow/VTK,demarle/VTK,ashray/VTK-EVM,jmerkow/VTK,sankhesh/VTK,mspark93/VTK,hendradarwin/VTK,collects/VTK,cjh1/VTK,SimVascular/VTK,berendkleinhaneveld/VTK,gram526/VTK,keithroe/vtkoptix,sankhesh/VTK,candy7393/VTK,ashray/VTK-EVM,gram526/VTK,msmolens/VTK,berendkleinhaneveld/VTK,candy7393/VTK,sumedhasingla/VTK,gram526/VTK,sumedhasingla/VTK,aashish24/VTK-old,mspark93/VTK,demarle/VTK,sankhesh/VTK,jmerkow/VTK,collects/VTK,ashray/VTK-EVM,hendradarwin/VTK,biddisco/VTK,jmerkow/VTK,hendradarwin/VTK,ashray/VTK-EVM,candy7393/VTK,sumedhasingla/VTK,ashray/VTK-EVM,sumedhasingla/VTK