Remove VTKM_EXEC_CONSTANT
If a global static array is declared with VTKM_EXEC_CONSTANT and the code is compiled by nvcc (for multibackend code) then the array is only accesible on the GPU. If for some reason a worklet fails on the cuda backend and it is re-executed on any of the CPU backends, it will continue to fail.
We couldn't find a simple way to declare the array once and have it available on both CPU and GPU. The approach we are using here is to declare the arrays as static inside some "Get" function which is marked as VTKM_EXEC_CONT.