Test reduce_by_key with thrust::seq in __device__ code.
Test reduce_by_key with thrust::seq in __device__ code.

GrimDerp/thrust,xiongzhanblake/thrust_src,egaburov/thrust,dachziegel/thrust,sarvex/thrust,egaburov/thrust,raygit/thrust,thrust/thrust,raygit/thrust,zeryx/thrust,egaburov/thrust,dachziegel/thrust,marksantos/thrust,andrewcorrigan/thrust-multi-permutation-iterator,thrust/thrust,zhenglaizhang/thrust,sarvex/thrust,sdalton1/thrust,zhenglaizhang/thrust,andrewcorrigan/thrust-multi-permutation-iterator,arnabgho/thrust,xiongzhanblake/thrust_src,thvasilo/thrust,xiongzhanblake/thrust_src,GrimDerp/thrust,jaredhoberock/thrust,mohamed-ali/thrust,zeryx/thrust,Ricardo666666/thrust,GrimDerp/thrust,mohamed-ali/thrust,marksantos/thrust,dachziegel/thrust,thvasilo/thrust,thrust/thrust,sarvex/thrust,jaredhoberock/thrust,thrust/thrust,sdalton1/thrust,xiongzhanblake/thrust,zeryx/thrust,xiongzhanblake/thrust,jaredhoberock/thrust,marksantos/thrust,zhenglaizhang/thrust,thrust/thrust,arnabgho/thrust,Ricardo666666/thrust,jaredhoberock/thrust,andrewcorrigan/thrust-multi-permutation-iterator,sdalton1/thrust,xiongzhanblake/thrust,Ricardo666666/thrust,arnabgho/thrust,thvasilo/thrust,mohamed-ali/thrust,jaredhoberock/thrust,raygit/thrust