Actually throw bad_alloc from cuda_cub::malloc.

thrust/system/cuda/detail/malloc_and_free.h

@@ -63,7 +63,7 @@ void *malloc(execution_policy<DerivedPolicy> &, std::size_t n)
   if(status != cudaSuccess)
   {
     cudaGetLastError(); // Clear global CUDA error state.
-    thrust::system::detail::bad_alloc(thrust::cuda_category().message(status).c_str());
+    throw thrust::system::detail::bad_alloc(thrust::cuda_category().message(status).c_str());
   }
 #else
   result = thrust::raw_pointer_cast(thrust::malloc(thrust::seq, n));