Fix TestingPointLocatorUniformGrid for double precision
There was an error in TestingPointLocatorUniformGrid in which it was creating arrays of type vtkm::Float32 and passing them to a worklet that expected vtkm::FloatDefault. This is corrected.
There was an error in TestingPointLocatorUniformGrid in which it was creating arrays of type vtkm::Float32 and passing them to a worklet that expected vtkm::FloatDefault. This is corrected.