headers: conform to the CheckGuard HeaderTest

Accelerators/Piston/vtkPistonReference.h

Charts/Core/vtkChartHistogram2D.h

Charts/Core/vtkContextPolygon.h

Charts/Core/vtkPlotHistogram2D.h

Common/Core/vtkAtomicTypeConcepts.h

Common/Core/vtkDataArrayTemplateHelper.h

Common/Core/vtkSMPTools.h

Common/Core/vtkVariantInlineOperators.h

Common/Core/vtkWin32Header.h

Common/DataModel/vtkAMRUtilities.h

Common/DataModel/vtkHierarchicalBoxDataIterator.h

Common/DataModel/vtkHierarchicalBoxDataSet.h

Common/DataModel/vtkMarchingCubesTriangleCases.h

Common/DataModel/vtkNonOverlappingAMR.h

Common/DataModel/vtkOverlappingAMR.h

Common/ExecutionModel/vtkExtentRCBPartitioner.h

Common/ExecutionModel/vtkImageToStructuredGrid.h

Common/ExecutionModel/vtkNonOverlappingAMRAlgorithm.h

Common/ExecutionModel/vtkOverlappingAMRAlgorithm.h

Common/ExecutionModel/vtkUniformGridAMRAlgorithm.h