clang-tidy: fix `readability-static-accessed-through-instance` lints

.clang-tidy

Charts/Core/vtkControlPointsItem.cxx

Common/Core/Testing/Cxx/TestObservers.cxx

Common/Core/Testing/Cxx/TestObserversPerformance.cxx

Common/DataModel/vtkBiQuadraticQuad.cxx

Common/DataModel/vtkBiQuadraticQuadraticHexahedron.cxx

Common/DataModel/vtkBiQuadraticQuadraticWedge.cxx

Common/DataModel/vtkBiQuadraticTriangle.cxx

Common/DataModel/vtkCubicLine.cxx

Common/DataModel/vtkDataSetAttributes.cxx

Common/DataModel/vtkGraph.cxx

Common/DataModel/vtkHexagonalPrism.cxx

Common/DataModel/vtkHexahedron.cxx

Common/DataModel/vtkHigherOrderWedge.cxx

Common/DataModel/vtkImplicitSelectionLoop.cxx

Common/DataModel/vtkLine.cxx

Common/DataModel/vtkPentagonalPrism.cxx

Common/DataModel/vtkPixel.cxx

Common/DataModel/vtkPlanesIntersection.cxx

Common/DataModel/vtkPolyData.cxx