Fix issue with CUDA and ArrayHandleMultiplexer

When you try to call the Reduce operation in the CUDA device adapter with a sufficently complex interator type, you get a compile error that says error: cannot pass an argument with a user-provided copy-constructor to a device-side kernel launch.

This appears to be a bug in either nvcc or Thrust. I believe it is related to the following reported issues:

• https://github.com/thrust/thrust/issues/928
• https://github.com/thrust/thrust/issues/1044

Work around this problem by making a special condition for calling Reduce with an ArrayHandleMultiplexer that calls the generic algorithm in DeviceAdapterAlgorithmGeneral instead of the algorithm in Thrust.