fix(Bench): correct index is now checked for statistical reductions with index
chore(Bench): remove custom CUDA library from bench program

the custom CUDA library is not publicly available
now that the bench properly tests multiple other, its presence in the bench program is no longer needed
improve(Bench): allow use of multi-channel images in bench program
feat: add support for multi-channel images for statistical reductions

min&max with index are still 1 channel only
feat(Bench): add tests for 4 channel statistical reductions