Consider swallowing errors in deallocation functions

[jaredhoberock]

thrust::system::cuda::free potentially throws an exception, which can lead to multiple exceptions in flight when this function is called from a destructor. This makes it impossible to do correct exception handling.

We should avoid throwing in functions named free or catch and swallow exceptions in destructors. Not sure what the right thing to do is.

[jaredhoberock]

thrust::system::cuda::free should probably ignore the error returned by cudaFree.

cudaFree will report an error if 1. the error is already set or 2. the pointer given to cudaFree is invalid.

case 1: if the error is already set, the error has probably already been reported via an exception currently in flight.

case 2: if the pointer given to cudaFree is invalid, we can specify that the behavior is undefined, as does std::free.

So it probably makes sense to swallow errors inside of thrust::system::cuda::free. That way, we don't need to try to handle exceptions in every single destructor which may indirectly call this function.

[jrhemstad]

Code in question: https://github.com/NVIDIA/thrust/blob/70ff3538dedab8cd87f5d4cae5b08060343686fa/thrust/system/cuda/detail/malloc_and_free.h#L111