See #775, the UniformLocator and RectilinearLocator shared many lines of code with vtkm::exec::CellLocatorUniformGrid and vtkm::exec::CellLocatorRectilinear. They probably were copy/paste of each other. This MR tries to consolidate them.
UniformLocator
RectilinearLocator
vtkm::exec::CellLocatorUniformGrid
vtkm::exec::CellLocatorRectilinear