External heap mrfd for fetch atomic

Removed external mrfd from fetch_atomic

Using atomic_nbi for fetch_nbi

Clean up

Added mr-descs for both atomic operations

Trial check for backtrace

Trial check removing mrfd for error case

Trial check#2 removing mrfd for error case

Trial check#3 removing mrfd for error case

Trial check#4 removing mrfd for error case

Trial check#5 removing mrfd for error case

Trial with sockets provider